1 00:00:02,440 --> 00:00:07,320 Speaker 1: Cappy Saturday. John Dalton was born on September fifth or sixth, 2 00:00:07,600 --> 00:00:10,479 Speaker 1: seventeen sixty six or two hundred and fifty nine years 3 00:00:10,520 --> 00:00:15,280 Speaker 1: ago today or possibly yesterday on the day this episode 4 00:00:15,320 --> 00:00:19,160 Speaker 1: is coming out. John Dalton was a physicist and a chemist, 5 00:00:19,239 --> 00:00:23,400 Speaker 1: but he's also known for his discoveries related to color 6 00:00:23,520 --> 00:00:28,120 Speaker 1: vision and color vision anomalies. Our episode on John Dalton 7 00:00:28,280 --> 00:00:31,200 Speaker 1: is Today's Saturday Classic, and it originally came out on 8 00:00:31,320 --> 00:00:38,040 Speaker 1: January twentieth, twenty twenty one. Enjoy Welcome to Stuff You 9 00:00:38,040 --> 00:00:48,120 Speaker 1: Missed in History Class, a production of iHeartRadio. Hello, and 10 00:00:48,159 --> 00:00:53,000 Speaker 1: welcome to the podcast. I'm Holly Frye and I'm Tracy V. Wilson. Tracy, 11 00:00:53,120 --> 00:00:55,760 Speaker 1: I bet this happened to you. I know it happened 12 00:00:55,800 --> 00:00:58,319 Speaker 1: to me. Like you must have had those moments as 13 00:00:58,320 --> 00:01:00,520 Speaker 1: a child where you thought you were being very insightful. 14 00:01:00,560 --> 00:01:02,480 Speaker 1: I know I certainly did where I was like, how 15 00:01:02,520 --> 00:01:04,559 Speaker 1: do I know that what I see is the same 16 00:01:04,600 --> 00:01:08,840 Speaker 1: thing as other people see? I had this exact Yes. Yes, 17 00:01:08,959 --> 00:01:11,240 Speaker 1: I also asked my mom one time. I was like, Mom, 18 00:01:11,280 --> 00:01:15,040 Speaker 1: how do we know that what I see as green 19 00:01:15,400 --> 00:01:18,000 Speaker 1: is the same thing as what you see as green? 20 00:01:19,520 --> 00:01:23,240 Speaker 1: And my mom stay at home mom with two little 21 00:01:23,319 --> 00:01:25,440 Speaker 1: children did not always have a lot of patience for 22 00:01:25,560 --> 00:01:33,480 Speaker 1: weird questions. And she was like, it's the same. I'm 23 00:01:33,480 --> 00:01:35,600 Speaker 1: not trying to drag my mom in any way. My 24 00:01:35,680 --> 00:01:40,480 Speaker 1: mom was like of our creativity and attentive to art. 25 00:01:40,600 --> 00:01:42,360 Speaker 1: But yeah, this was a case where I liked I 26 00:01:42,400 --> 00:01:44,600 Speaker 1: just asked her in a question she was not prepared 27 00:01:44,640 --> 00:01:48,840 Speaker 1: for question time. Here is the thing. I asked the 28 00:01:48,920 --> 00:01:53,520 Speaker 1: same question of my father, who I did not know, 29 00:01:54,880 --> 00:01:56,919 Speaker 1: and I don't know that he knew at the time, 30 00:01:57,600 --> 00:02:04,240 Speaker 1: did not see color the way, so he was trying 31 00:02:04,280 --> 00:02:07,000 Speaker 1: to describe things. And I just remember, I mean, I 32 00:02:07,040 --> 00:02:09,160 Speaker 1: was probably like seven or eight, already kind of a 33 00:02:09,160 --> 00:02:11,080 Speaker 1: smart alec and I was just like, okay, this is 34 00:02:11,120 --> 00:02:13,480 Speaker 1: going nowhere. I'm out. So maybe just saying green is 35 00:02:13,520 --> 00:02:16,000 Speaker 1: green was a really a better route because that led 36 00:02:16,040 --> 00:02:19,080 Speaker 1: to a lot of confusion in our lives for a 37 00:02:19,120 --> 00:02:22,520 Speaker 1: moment until we finally put the pieces together right, And 38 00:02:22,560 --> 00:02:24,600 Speaker 1: really what happened was that. And I don't mean to 39 00:02:24,680 --> 00:02:27,919 Speaker 1: drag my father, but like he was career military, so 40 00:02:28,639 --> 00:02:31,720 Speaker 1: he's now retired, but his clothes were like sort of 41 00:02:31,760 --> 00:02:37,799 Speaker 1: prescribed for sure. When he stopped being constantly on active 42 00:02:37,919 --> 00:02:40,720 Speaker 1: duty and started picking out his own clothes. So things 43 00:02:40,760 --> 00:02:45,959 Speaker 1: became readily apparent, which is that that does not go together. 44 00:02:46,120 --> 00:02:49,640 Speaker 1: My dude, Yes, they look they're practically the same color. Oh, 45 00:02:49,760 --> 00:02:54,000 Speaker 1: we should address this, right. That's we never knew for years, 46 00:02:54,280 --> 00:02:57,400 Speaker 1: when you're wearing like jeans and a plaid shirt in 47 00:02:57,440 --> 00:02:59,240 Speaker 1: your off time and then a uniform the rest of 48 00:02:59,240 --> 00:03:03,200 Speaker 1: the time, it would never come up. Now we learned. 49 00:03:03,960 --> 00:03:06,480 Speaker 1: But this curiosity about whether other people see the way 50 00:03:06,520 --> 00:03:09,440 Speaker 1: that you see is really what drives a lot of 51 00:03:09,480 --> 00:03:12,960 Speaker 1: scientific discovery. And we are talking about somebody who was 52 00:03:13,080 --> 00:03:16,240 Speaker 1: curious and did a lot of scientific discovery. But in 53 00:03:16,280 --> 00:03:19,799 Speaker 1: the case of this subject, who was very well known 54 00:03:19,800 --> 00:03:22,799 Speaker 1: and respected in his day, he just didn't think about 55 00:03:22,840 --> 00:03:26,080 Speaker 1: how he or anyone else saw color until he kind 56 00:03:26,120 --> 00:03:30,040 Speaker 1: of stumbled into it while studying plants and realizing that 57 00:03:30,200 --> 00:03:32,760 Speaker 1: his vision might be different from other people. And that's 58 00:03:32,840 --> 00:03:36,160 Speaker 1: John Dalton, And really John Dalton is far more famous 59 00:03:36,200 --> 00:03:39,320 Speaker 1: for his work in atomic theory, which builds the foundations 60 00:03:39,360 --> 00:03:43,360 Speaker 1: of organic chemistry, but he also wrote one of the 61 00:03:43,400 --> 00:03:47,320 Speaker 1: first really thorough descriptions of what he called anomalist's vision, 62 00:03:47,720 --> 00:03:50,640 Speaker 1: meaning that he realized he was not perceiving color in 63 00:03:50,680 --> 00:03:53,400 Speaker 1: the same way as other people, and his descriptions are 64 00:03:53,600 --> 00:03:56,400 Speaker 1: very entertaining. We're going to read some of them, so 65 00:03:56,440 --> 00:03:58,680 Speaker 1: today we will talk a little bit about his life, 66 00:03:59,240 --> 00:04:03,680 Speaker 1: but mostly about this sort of pocket in his scientific work, 67 00:04:03,960 --> 00:04:06,560 Speaker 1: where he made a brief foray into exploring the world 68 00:04:06,600 --> 00:04:09,920 Speaker 1: of photoreceptors and color perception, although he didn't use those 69 00:04:09,960 --> 00:04:13,720 Speaker 1: words for it. Color blindness is a term that's falling 70 00:04:13,720 --> 00:04:17,640 Speaker 1: out of favor because it's not really accurate. Colorblind suggests 71 00:04:17,640 --> 00:04:20,679 Speaker 1: that somebody can't see color at all, but most people 72 00:04:20,760 --> 00:04:25,080 Speaker 1: who have historically been diagnosed with color blindness can see colors, 73 00:04:25,080 --> 00:04:28,960 Speaker 1: they just see them differently. So defective color vision or 74 00:04:29,080 --> 00:04:34,320 Speaker 1: color vision deficiency are becoming more preferred terms. I feel 75 00:04:34,320 --> 00:04:38,320 Speaker 1: like I see people describing themselves as colorblind still quite 76 00:04:38,360 --> 00:04:41,320 Speaker 1: a lot. So this is something that's evolving. We're still 77 00:04:41,400 --> 00:04:44,240 Speaker 1: kind of at the beginning of the scientific community shifting 78 00:04:44,320 --> 00:04:48,520 Speaker 1: to these different terms, and it's really about clarity more 79 00:04:48,560 --> 00:04:52,279 Speaker 1: than anything else, right, like, no, you do see color. 80 00:04:52,279 --> 00:04:55,760 Speaker 1: We'll talk about one exception, but just differently, So we 81 00:04:55,839 --> 00:04:58,640 Speaker 1: need to make a clearer term for it that's not misleading. 82 00:04:59,480 --> 00:05:03,680 Speaker 1: And color vision deficiency is the inability to distinguish specific 83 00:05:03,720 --> 00:05:07,599 Speaker 1: colors red, green, and blue, and to be diagnosed as 84 00:05:07,680 --> 00:05:11,599 Speaker 1: colorblind historically or color vision deficient. Now, a person only 85 00:05:11,640 --> 00:05:15,160 Speaker 1: needs to have an inability to distinguish one of these colors, 86 00:05:15,600 --> 00:05:17,960 Speaker 1: but it is possible for someone who has color vision 87 00:05:17,960 --> 00:05:22,000 Speaker 1: deficiency to be unable to distinguish all three. So in 88 00:05:22,200 --> 00:05:26,440 Speaker 1: your retina, you have cells called rods, which perceive light, 89 00:05:26,680 --> 00:05:30,320 Speaker 1: and then three types of cells called cones. Cones are 90 00:05:30,320 --> 00:05:34,000 Speaker 1: really the important factor here. They are the photoreceptive cells 91 00:05:34,040 --> 00:05:37,760 Speaker 1: that enable us to perceive color. The human retina contains 92 00:05:37,800 --> 00:05:42,839 Speaker 1: six million cones. Red sensing cones make up sixty percent 93 00:05:42,920 --> 00:05:47,240 Speaker 1: of the total number of cone cells, green sensing cones 94 00:05:47,279 --> 00:05:50,320 Speaker 1: make up thirty percent, and blue sensing tones make up 95 00:05:50,520 --> 00:05:53,400 Speaker 1: the remaining ten percent. So if all of your cone 96 00:05:53,400 --> 00:05:56,560 Speaker 1: cells are functioning normally, you are said to have trichromacy, 97 00:05:56,960 --> 00:06:00,240 Speaker 1: meaning you can see three try of these colors. They 98 00:06:00,240 --> 00:06:04,359 Speaker 1: combine to create standard vision. But it is also possible 99 00:06:04,400 --> 00:06:07,320 Speaker 1: to have dichromasy with only two types of cone cells 100 00:06:07,360 --> 00:06:11,440 Speaker 1: present or functioning, or even monochromacy where only one type 101 00:06:11,440 --> 00:06:14,800 Speaker 1: of cone is functioning. Monochromacy is a little bit tricky 102 00:06:14,839 --> 00:06:17,360 Speaker 1: because it can also be used to describe a scenario 103 00:06:17,480 --> 00:06:20,520 Speaker 1: where none of a person's cones are functioning, and a 104 00:06:20,560 --> 00:06:23,880 Speaker 1: person who has monochromacy may have other vision issues as well, 105 00:06:24,080 --> 00:06:26,919 Speaker 1: And monochromacy that we just talked about with no cone 106 00:06:26,960 --> 00:06:29,800 Speaker 1: function is kind of the one variation in all of 107 00:06:29,800 --> 00:06:33,279 Speaker 1: this where the color blind label would be actually pretty accurate, 108 00:06:33,360 --> 00:06:37,320 Speaker 1: because everything to them appears not in the rainbow of colors, 109 00:06:37,320 --> 00:06:39,880 Speaker 1: but as a shade of gray most of the time. 110 00:06:40,000 --> 00:06:43,520 Speaker 1: Dichromacy manifests itself in a way that a person can't 111 00:06:43,560 --> 00:06:48,440 Speaker 1: see a difference between red and green, and dichromacy of 112 00:06:48,480 --> 00:06:51,919 Speaker 1: this nature is broken down into separate classifications based on 113 00:06:52,160 --> 00:06:54,839 Speaker 1: which types of cones do and don't work in a 114 00:06:54,880 --> 00:06:59,360 Speaker 1: person's retina. Protonopia describes a state of not being able 115 00:06:59,400 --> 00:07:02,360 Speaker 1: to see red, and due to anopia is a case 116 00:07:02,400 --> 00:07:05,919 Speaker 1: where the red cones function but the green cones do not. 117 00:07:06,680 --> 00:07:09,760 Speaker 1: Blue yellow color deficiency, which is a little rarer, is 118 00:07:09,840 --> 00:07:13,560 Speaker 1: similarly broken down into classifications based on its specific nature 119 00:07:13,600 --> 00:07:16,200 Speaker 1: in a given person. So someone with a lack of 120 00:07:16,280 --> 00:07:19,160 Speaker 1: blue cones is said to have tritonopia, and if they 121 00:07:19,160 --> 00:07:22,280 Speaker 1: have blue cones but reduce sensitivity to that color, it 122 00:07:22,360 --> 00:07:26,880 Speaker 1: is actually described as tritinomaly. An all color vision deficiency 123 00:07:26,960 --> 00:07:30,080 Speaker 1: can fall on a spectrum. Some people have a diminished 124 00:07:30,120 --> 00:07:34,000 Speaker 1: ability to distinguish red from green, for example, but they're 125 00:07:34,080 --> 00:07:38,920 Speaker 1: able to see difference within specific shades of these colors. Yeah. 126 00:07:38,920 --> 00:07:41,280 Speaker 1: Sometimes you know, people can't hit the lighter tones of 127 00:07:41,320 --> 00:07:43,720 Speaker 1: the darker tones get real muddy, but they can see 128 00:07:43,920 --> 00:07:47,720 Speaker 1: different shades. It's all. It manifests in many different ways, 129 00:07:48,320 --> 00:07:50,920 Speaker 1: and in the United States an estimated five to ten 130 00:07:51,000 --> 00:07:55,160 Speaker 1: percent of the population have some form of color vision deficiency. 131 00:07:55,960 --> 00:07:59,040 Speaker 1: Usually this gets tested for when people are kids, and 132 00:07:59,120 --> 00:08:02,760 Speaker 1: more boys than girls have colored vision deficiency, and the 133 00:08:02,760 --> 00:08:05,960 Speaker 1: percentage shifts based on race. So there was a twenty 134 00:08:06,000 --> 00:08:09,200 Speaker 1: fourteen study that gets cited a lot. This was published 135 00:08:09,200 --> 00:08:12,960 Speaker 1: in the journal Optthalmology, and it had taken studies of 136 00:08:13,040 --> 00:08:16,880 Speaker 1: the color vision of four thousand California children ranging in 137 00:08:16,920 --> 00:08:20,040 Speaker 1: age from three to six. And in this study it 138 00:08:20,080 --> 00:08:22,360 Speaker 1: was found that among the girls, less than half a 139 00:08:22,400 --> 00:08:25,920 Speaker 1: percent of them exhibited signs of color vision deficiency, regardless 140 00:08:25,920 --> 00:08:29,520 Speaker 1: of race, but in boys the numbers were different. Six 141 00:08:29,600 --> 00:08:32,200 Speaker 1: percent of the white boys in the study were diagnosed 142 00:08:32,200 --> 00:08:35,760 Speaker 1: with color vision deficiency, three percent of the Asian boys 143 00:08:35,800 --> 00:08:39,000 Speaker 1: had some form of color vision deficiency. It was found 144 00:08:39,040 --> 00:08:41,640 Speaker 1: in fewer than three percent of the Latino boys and 145 00:08:41,720 --> 00:08:46,120 Speaker 1: less than two percent of Black boys. Genetically, boys are 146 00:08:46,200 --> 00:08:50,120 Speaker 1: more likely to have red green color vision deficiency because 147 00:08:50,160 --> 00:08:53,760 Speaker 1: they only need to inherit it from their mother. It 148 00:08:53,800 --> 00:08:58,920 Speaker 1: is a recessive characteristic that's associated with the X chromosome. 149 00:08:59,600 --> 00:09:04,199 Speaker 1: So if a female inherits the trait from her mother 150 00:09:04,360 --> 00:09:08,080 Speaker 1: but not her father, she'll generally have normal color vision 151 00:09:08,880 --> 00:09:12,880 Speaker 1: she only has that one X chromosome, but then she 152 00:09:12,880 --> 00:09:15,400 Speaker 1: could pass the trait onto her own children. And this 153 00:09:15,520 --> 00:09:18,720 Speaker 1: is different from blue yellow color vision deficiency, which is 154 00:09:18,720 --> 00:09:21,360 Speaker 1: a dominant characteristic, and so that only needs to be 155 00:09:21,400 --> 00:09:24,760 Speaker 1: inherited from one parent, and it is not linked to 156 00:09:24,800 --> 00:09:29,199 Speaker 1: a person's sex. I'm just gonna say these are related 157 00:09:29,240 --> 00:09:34,320 Speaker 1: to sex and not to gender. That's the different thing. Yeah, 158 00:09:34,400 --> 00:09:37,120 Speaker 1: we're going with kind of that twenty fourteen studies Separation 159 00:09:37,200 --> 00:09:40,079 Speaker 1: of Boys and Girls, which simplifies the whole discussion, and 160 00:09:40,200 --> 00:09:45,520 Speaker 1: is sex assigned at births not necessarily? How if they 161 00:09:45,520 --> 00:09:47,480 Speaker 1: did that, I would be fascinated if they did the 162 00:09:47,520 --> 00:09:50,360 Speaker 1: same exact test today and how they would break it out, 163 00:09:50,440 --> 00:09:54,240 Speaker 1: because it's things have shifted a bit. So if anybody 164 00:09:54,280 --> 00:09:56,440 Speaker 1: knows of any studies similar to that going on today, 165 00:09:56,600 --> 00:09:59,920 Speaker 1: I'm very curious. But here's the thing. You're probably wonder 166 00:10:00,120 --> 00:10:02,559 Speaker 1: how we figured all of this out. And in the 167 00:10:02,640 --> 00:10:06,480 Speaker 1: late eighteenth century, this idea of people perceiving color differently 168 00:10:06,720 --> 00:10:10,640 Speaker 1: than most humans was certainly not unknown. King George the Third, 169 00:10:10,679 --> 00:10:15,120 Speaker 1: for example, reportedly discussed this with an English novelist, Fanny Burney, 170 00:10:15,200 --> 00:10:18,480 Speaker 1: at court in seventeen eighty five, and there were some 171 00:10:18,600 --> 00:10:22,319 Speaker 1: theories about what caused color vision anomalies published in Germany 172 00:10:22,360 --> 00:10:25,800 Speaker 1: in the late seventeen hundreds, but the first systematic analysis 173 00:10:25,840 --> 00:10:29,160 Speaker 1: of color vision deficiency appears in seventeen ninety three, at 174 00:10:29,200 --> 00:10:31,440 Speaker 1: least the first that we know of, and that brings 175 00:10:31,520 --> 00:10:33,240 Speaker 1: us to the person we mentioned at the top of 176 00:10:33,240 --> 00:10:36,720 Speaker 1: the show, John Dalton. John Dalton was born in early 177 00:10:36,760 --> 00:10:40,560 Speaker 1: September seventeen sixty six. His actual date of birth is 178 00:10:40,600 --> 00:10:45,560 Speaker 1: either September fifth or September sixth. His parents, Joseph Dalton 179 00:10:45,720 --> 00:10:49,120 Speaker 1: and Deborah green Up Dalton, were Quakers. His father made 180 00:10:49,160 --> 00:10:52,240 Speaker 1: a living as a weaver. The Dalton's had three children 181 00:10:52,280 --> 00:10:55,599 Speaker 1: who lived to adulthood, and John was the youngest of them, 182 00:10:55,800 --> 00:10:59,240 Speaker 1: and as a child, John attended a Quaker school and 183 00:10:59,320 --> 00:11:02,960 Speaker 1: that school chain hands. When John was twelve, John Fletcher, 184 00:11:03,000 --> 00:11:05,160 Speaker 1: the man who had been running it, gave it to 185 00:11:05,280 --> 00:11:09,200 Speaker 1: John Dalton's older brother, Jonathan Dalton, and then Jonathan enlisted 186 00:11:09,240 --> 00:11:12,520 Speaker 1: John's assistance in this new role, and this set John 187 00:11:12,559 --> 00:11:15,600 Speaker 1: on a path as an educator. Just kind of delights 188 00:11:15,640 --> 00:11:20,000 Speaker 1: me that they had a John and a Jonathan. It 189 00:11:20,040 --> 00:11:23,520 Speaker 1: makes me giggle as well. John and Jonathan expanded their 190 00:11:23,559 --> 00:11:26,600 Speaker 1: new careers by taking over a school in Kendall, England, 191 00:11:26,720 --> 00:11:30,559 Speaker 1: when John was just fourteen. This was a larger operation 192 00:11:30,840 --> 00:11:33,360 Speaker 1: than the Quaker grammar school they had been running, and 193 00:11:33,400 --> 00:11:36,360 Speaker 1: it included students who boarded as well as day students. 194 00:11:36,640 --> 00:11:40,839 Speaker 1: That's totaled about five dozen students in all. And John 195 00:11:40,960 --> 00:11:43,200 Speaker 1: was sort of learning on the job. He was studying 196 00:11:43,200 --> 00:11:46,520 Speaker 1: with scholars to learn math, Latin, Greek and science to 197 00:11:46,679 --> 00:11:48,960 Speaker 1: stay ahead of his students and to be able to 198 00:11:48,960 --> 00:11:52,640 Speaker 1: speak on the subjects of their curriculum. And keep in mind, 199 00:11:52,679 --> 00:11:57,080 Speaker 1: again he's like fourteen fifteen at this fight, so he 200 00:11:57,160 --> 00:11:59,959 Speaker 1: is taking in a lot of information. And he stayed 201 00:12:00,160 --> 00:12:02,040 Speaker 1: in that job for a dozen years and then at 202 00:12:02,040 --> 00:12:04,640 Speaker 1: the age of twenty seven, John moved on to a 203 00:12:04,679 --> 00:12:08,000 Speaker 1: new professional post as a mathematics teacher at New College, 204 00:12:08,000 --> 00:12:10,640 Speaker 1: and this was in Manchester. And he found all this 205 00:12:10,720 --> 00:12:13,520 Speaker 1: a little bit frustrating though, because his workload in that 206 00:12:13,679 --> 00:12:16,680 Speaker 1: job prevented him from having time to pursue his own 207 00:12:16,720 --> 00:12:20,640 Speaker 1: scientific study. So he switched gears and decided that he 208 00:12:20,640 --> 00:12:23,120 Speaker 1: would become a private tutor so that he could manage 209 00:12:23,120 --> 00:12:25,360 Speaker 1: his own time in a way that would enable him 210 00:12:25,400 --> 00:12:28,200 Speaker 1: to carry on with his side work. At this point, 211 00:12:28,200 --> 00:12:31,400 Speaker 1: his work outside of his daily teaching task was focused 212 00:12:31,480 --> 00:12:35,000 Speaker 1: largely on meteorology. He had been publishing articles in the 213 00:12:35,040 --> 00:12:38,920 Speaker 1: subject for several years, but he kept studying other sciences 214 00:12:38,960 --> 00:12:42,480 Speaker 1: as well, and it was through these studies that he 215 00:12:42,520 --> 00:12:45,480 Speaker 1: wound up writing a paper that expounded on the idea 216 00:12:45,640 --> 00:12:49,560 Speaker 1: that not everyone saw colors in the same way. So 217 00:12:49,840 --> 00:12:52,360 Speaker 1: this was not the first time the mention of non 218 00:12:52,360 --> 00:12:56,360 Speaker 1: standard color vision appeared in print. As we said earlier, surely, 219 00:12:56,440 --> 00:12:59,439 Speaker 1: color vision diviiciency has been in play almost as long 220 00:12:59,440 --> 00:13:02,680 Speaker 1: as humans have existed, and even before Dalton there had 221 00:13:02,760 --> 00:13:06,080 Speaker 1: been some mentions of it, including a write up of 222 00:13:06,120 --> 00:13:09,040 Speaker 1: a man named Thomas Harris that was published in Philosophical 223 00:13:09,040 --> 00:13:14,199 Speaker 1: Transactions and that described Harris's Inability to Distinguish Colors, which 224 00:13:14,440 --> 00:13:17,400 Speaker 1: was published in seventeen seventy seven. We're going to come 225 00:13:17,400 --> 00:13:20,240 Speaker 1: back to Harris and we'll talk first more about John Dalton. 226 00:13:20,440 --> 00:13:21,880 Speaker 1: But before we do all of that, we're going to 227 00:13:21,960 --> 00:13:34,640 Speaker 1: pause for a brief sponsor break. John Dalton presented his paper, 228 00:13:34,720 --> 00:13:37,559 Speaker 1: which was titled Extraordinary Facts relating to the Vision of 229 00:13:37,640 --> 00:13:42,280 Speaker 1: Colors with Observations by Mister John Dalton, at Manchester's Literary 230 00:13:42,320 --> 00:13:46,240 Speaker 1: and Philosophical Society on October thirty first, seventeen ninety four. 231 00:13:47,000 --> 00:13:50,360 Speaker 1: He had joined the Society upon moving to Manchester. And 232 00:13:50,440 --> 00:13:53,000 Speaker 1: as scientific papers go, this one is kind of unique 233 00:13:53,040 --> 00:13:55,880 Speaker 1: in that Dalton himself is really the subject of the paper, 234 00:13:56,000 --> 00:14:00,000 Speaker 1: or at least his vision was. That text opens with quote, 235 00:14:00,360 --> 00:14:04,760 Speaker 1: it has been observed that our ideas of colors, sounds, tastes, 236 00:14:04,960 --> 00:14:09,280 Speaker 1: et cetera, excited by the same object, may be very 237 00:14:09,320 --> 00:14:12,760 Speaker 1: different in themselves without our being aware of it. He 238 00:14:12,840 --> 00:14:15,800 Speaker 1: goes on quote I was always of the opinion, though 239 00:14:15,840 --> 00:14:19,080 Speaker 1: I might not often mention it, that several colors were 240 00:14:19,280 --> 00:14:24,440 Speaker 1: injudiciously named. The term pink in reference to the flower 241 00:14:24,520 --> 00:14:28,080 Speaker 1: of that name seemed proper enough. But when the term 242 00:14:28,320 --> 00:14:32,120 Speaker 1: red was substituted for pink. I thought it highly improper. 243 00:14:32,280 --> 00:14:35,680 Speaker 1: It should have been blue in my apprehension, as pink 244 00:14:35,760 --> 00:14:39,960 Speaker 1: and blue appear to me very nearly allied, whilst pink 245 00:14:40,000 --> 00:14:45,600 Speaker 1: and red have scarcely any relation. He goes on in 246 00:14:45,640 --> 00:14:48,400 Speaker 1: his introduction to mention how he had learned about light 247 00:14:48,440 --> 00:14:51,200 Speaker 1: and optics in his scientific studies, but he hadn't really 248 00:14:51,200 --> 00:14:54,800 Speaker 1: thought about applying any of that information to colors because 249 00:14:54,840 --> 00:14:58,000 Speaker 1: that entire area, the idea of color, seemed kind of 250 00:14:58,040 --> 00:15:00,120 Speaker 1: confused and odd to them. Like he really was, like, 251 00:15:00,120 --> 00:15:02,200 Speaker 1: why would people group these colors together? It doesn't make 252 00:15:02,200 --> 00:15:05,560 Speaker 1: any sense, But I guess that's how we've always done it. 253 00:15:05,560 --> 00:15:08,400 Speaker 1: It was not until he turned his scientific work to 254 00:15:08,440 --> 00:15:11,840 Speaker 1: botany that he really started thinking about why some color 255 00:15:11,880 --> 00:15:15,720 Speaker 1: groupings just made no sense. And this study prompted him 256 00:15:15,720 --> 00:15:19,440 Speaker 1: to ask other people questions about colors. He actually uses 257 00:15:19,480 --> 00:15:22,840 Speaker 1: the example in this paper of asking a person whether 258 00:15:22,880 --> 00:15:26,000 Speaker 1: a flower was blue or pink. But they always just 259 00:15:26,040 --> 00:15:28,480 Speaker 1: thought he must be joking because the queries came off 260 00:15:28,480 --> 00:15:31,040 Speaker 1: as so completely absurd to them. So he just thought 261 00:15:31,120 --> 00:15:35,520 Speaker 1: everybody had this weird relationship with color, even though he 262 00:15:35,600 --> 00:15:38,840 Speaker 1: thought colors made no sense. It didn't really occur to 263 00:15:38,920 --> 00:15:42,240 Speaker 1: him to wonder if there was something unusual about the 264 00:15:42,240 --> 00:15:45,960 Speaker 1: way he was perceiving colors. It was a moment in 265 00:15:46,080 --> 00:15:49,760 Speaker 1: seventeen ninety two, two years before he presented his paper, 266 00:15:49,760 --> 00:15:53,160 Speaker 1: that really gave him this moment of pause. That moment 267 00:15:53,400 --> 00:15:57,400 Speaker 1: happened when he was looking at a geranium by candlelight. 268 00:15:57,920 --> 00:16:00,720 Speaker 1: So he had frequently seen these flowers in this particular 269 00:16:00,880 --> 00:16:04,480 Speaker 1: variety he was looking at were in fact pink in daylight, 270 00:16:04,760 --> 00:16:07,960 Speaker 1: and to him, in daylight he perceived them as sky blue. 271 00:16:08,480 --> 00:16:12,080 Speaker 1: But by candlelight, he saw this flower as a vibrant red, 272 00:16:12,680 --> 00:16:15,400 Speaker 1: And this significant shift in their color due to lighting 273 00:16:15,480 --> 00:16:19,560 Speaker 1: changes startled him and led him to make a quick 274 00:16:19,600 --> 00:16:22,080 Speaker 1: study by asking a number of friends to look at 275 00:16:22,120 --> 00:16:26,120 Speaker 1: these same flowers in both daylight and candlelight. All the 276 00:16:26,160 --> 00:16:28,520 Speaker 1: people he initially asked about it saw them as pink 277 00:16:28,640 --> 00:16:32,800 Speaker 1: in both lighting conditions, except for his brother, who perceived 278 00:16:32,880 --> 00:16:35,240 Speaker 1: that same shift of them being sky blue in the 279 00:16:35,320 --> 00:16:39,160 Speaker 1: day and red in candle light. This experience caused him 280 00:16:39,160 --> 00:16:42,280 Speaker 1: to start a more structured study of light and color, 281 00:16:42,720 --> 00:16:45,560 Speaker 1: which he did with an assistant who had quote normal 282 00:16:45,680 --> 00:16:50,040 Speaker 1: color vision. First, he used a prism to project sunlight 283 00:16:50,080 --> 00:16:52,680 Speaker 1: into a dark room and then recorded the number of 284 00:16:52,760 --> 00:16:55,440 Speaker 1: colors that various people saw in that band of light. 285 00:16:55,600 --> 00:16:59,640 Speaker 1: Most of them saw six red, orange, yellow, green, blue, 286 00:16:59,680 --> 00:17:03,320 Speaker 1: and pearl. He does mention that purple is separated into 287 00:17:03,360 --> 00:17:07,960 Speaker 1: indigo in violet in Newton's writings on color for the 288 00:17:07,960 --> 00:17:11,160 Speaker 1: purposes of a person simply looking at a band of light, 289 00:17:11,640 --> 00:17:14,640 Speaker 1: that distinction is really nominal. I think we talked about 290 00:17:14,640 --> 00:17:17,000 Speaker 1: this in one of our episodes that touched on Newton previously. 291 00:17:17,160 --> 00:17:19,560 Speaker 1: He put indigo and violet in there separately because he 292 00:17:19,600 --> 00:17:24,160 Speaker 1: wanted there to be seven. So that's why people typically 293 00:17:24,160 --> 00:17:27,040 Speaker 1: don't actually see them as two estate shades in light 294 00:17:27,080 --> 00:17:30,680 Speaker 1: from a prism. Yeah, or you'll see what you think 295 00:17:30,800 --> 00:17:34,200 Speaker 1: is maybe a slight difference, but it's hard to be sure. Yeah, 296 00:17:34,640 --> 00:17:38,520 Speaker 1: So for Dalton, he just called that one thing, it's purple. 297 00:17:39,320 --> 00:17:41,880 Speaker 1: When Dalton looked at the prismatic light, though, he could 298 00:17:41,880 --> 00:17:46,920 Speaker 1: only make out two or sometimes three colors, so generally 299 00:17:46,960 --> 00:17:50,080 Speaker 1: he just saw yellow and blue, or sometimes he would 300 00:17:50,080 --> 00:17:53,639 Speaker 1: see yellow, blue and a little bit of purple. And 301 00:17:53,720 --> 00:17:55,959 Speaker 1: through his work he identified that the band that he 302 00:17:56,040 --> 00:17:59,439 Speaker 1: saw as yellow was where other people were seeing red, orange, yellow, 303 00:17:59,480 --> 00:18:02,720 Speaker 1: and green, and he wrote quote that part of the image, 304 00:18:02,760 --> 00:18:05,600 Speaker 1: which others call red, appears to me little more than 305 00:18:05,600 --> 00:18:10,000 Speaker 1: a shade or a defect of light. After that, the orange, yellow, 306 00:18:10,040 --> 00:18:13,680 Speaker 1: and green seem one color which descends pretty uniformly from 307 00:18:13,720 --> 00:18:17,000 Speaker 1: an intense to a rare yellow, making what I should 308 00:18:17,000 --> 00:18:20,719 Speaker 1: call different shades of yellow. Dalton's perception of blue and 309 00:18:20,800 --> 00:18:23,960 Speaker 1: purple aligned with what other people were seeing, and the 310 00:18:24,040 --> 00:18:27,280 Speaker 1: contrast between the end of his band of yellow and 311 00:18:27,320 --> 00:18:30,760 Speaker 1: the adjacent blue was really sharp. So next he did 312 00:18:30,800 --> 00:18:34,640 Speaker 1: the same collecting of perceptions from himself and others when 313 00:18:34,680 --> 00:18:38,240 Speaker 1: looking at candle light projected through a prism, and these 314 00:18:38,240 --> 00:18:41,760 Speaker 1: results were mostly the same. The only exception that Dalton 315 00:18:41,840 --> 00:18:44,159 Speaker 1: calls out is that for him, the red edge of 316 00:18:44,200 --> 00:18:47,080 Speaker 1: the image looks more vivid in candle light than it 317 00:18:47,160 --> 00:18:50,560 Speaker 1: did looking at sunlight under the same conditions of being 318 00:18:50,600 --> 00:18:54,280 Speaker 1: put through a prism. Dalton's paper next breaks out studies 319 00:18:54,280 --> 00:18:58,080 Speaker 1: of specific colors as he had always perceived them. He 320 00:18:58,359 --> 00:19:01,640 Speaker 1: starts out by describing color grouped with red as they 321 00:19:01,640 --> 00:19:05,760 Speaker 1: appear in the daylight versus candlelight. His description of Crimson 322 00:19:05,840 --> 00:19:09,800 Speaker 1: is pretty charming. Quote Crimson has a grave appearance, being 323 00:19:09,880 --> 00:19:15,159 Speaker 1: the reverse of every showy and splendid color. A similarly 324 00:19:15,320 --> 00:19:18,600 Speaker 1: quaint description is his description of pink. He breaks that 325 00:19:18,720 --> 00:19:22,080 Speaker 1: down as nine parts light blue and one part red 326 00:19:22,240 --> 00:19:26,119 Speaker 1: quote or some other color which has no other effect 327 00:19:26,240 --> 00:19:29,200 Speaker 1: than to make the light blue appear dull and faded 328 00:19:29,240 --> 00:19:32,520 Speaker 1: a little. He also lists out all the flowers that 329 00:19:32,600 --> 00:19:35,080 Speaker 1: to him look blue to give the reader a sense 330 00:19:35,119 --> 00:19:38,080 Speaker 1: of context. When he says he says pinks and reds 331 00:19:38,160 --> 00:19:41,720 Speaker 1: as blue, blood, he says appears to him as the 332 00:19:41,760 --> 00:19:45,159 Speaker 1: color most people call bottle green, and he mentions that 333 00:19:45,240 --> 00:19:48,720 Speaker 1: if he saw a light colored stocking that was spattered 334 00:19:48,720 --> 00:19:52,280 Speaker 1: with either fresh blood or dirt, he would not be 335 00:19:52,320 --> 00:19:56,920 Speaker 1: able to tell the difference visually. I love this entire 336 00:19:57,000 --> 00:20:00,359 Speaker 1: paper so much. It's exactly like this the whole way through. 337 00:20:01,480 --> 00:20:04,760 Speaker 1: His turn of phrase is quite quite charming and endearing. 338 00:20:05,520 --> 00:20:08,359 Speaker 1: He goes on to describe the significant change that red 339 00:20:08,480 --> 00:20:11,480 Speaker 1: undergoes for him when viewed in candlelight. He describes it 340 00:20:11,520 --> 00:20:14,000 Speaker 1: as much more vivid, and the blue no longer being 341 00:20:14,040 --> 00:20:18,480 Speaker 1: present and instead replaced by yellow tones. While he found 342 00:20:18,680 --> 00:20:22,359 Speaker 1: most reds and pinks quite drowned by daylight, in candlelight, 343 00:20:22,440 --> 00:20:26,479 Speaker 1: they became really vivid and even exciting. Orange and yellow, 344 00:20:26,520 --> 00:20:29,320 Speaker 1: he says, are not too different for him than anyone else. 345 00:20:29,880 --> 00:20:33,159 Speaker 1: When he moves on to discussing green, he writes, quote, 346 00:20:33,200 --> 00:20:37,600 Speaker 1: I take my standard idea from grass. This appears to 347 00:20:37,640 --> 00:20:40,439 Speaker 1: me very little different from red. The face of a 348 00:20:40,560 --> 00:20:43,359 Speaker 1: laurel leaf is a good match to a stick of 349 00:20:43,520 --> 00:20:47,320 Speaker 1: sealing wax. Hence, it will be immediately concluded that I 350 00:20:47,400 --> 00:20:51,960 Speaker 1: see either red or green, or both different from other people. 351 00:20:52,560 --> 00:20:55,480 Speaker 1: The fact is I believe that they both appear different 352 00:20:55,560 --> 00:20:59,400 Speaker 1: to me from what they do to others. He concludes 353 00:20:59,440 --> 00:21:02,439 Speaker 1: that blue he generally sees the same as other people, 354 00:21:02,560 --> 00:21:05,040 Speaker 1: and purple is just a little bit different from blue. 355 00:21:05,840 --> 00:21:08,879 Speaker 1: He described brown in the same creative way that he 356 00:21:08,920 --> 00:21:12,359 Speaker 1: does other colors, writing quote, my idea of brown I 357 00:21:12,400 --> 00:21:16,080 Speaker 1: obtain from a piece of white paper heated almost to ignition. 358 00:21:16,960 --> 00:21:20,439 Speaker 1: He also notes that seeing colors in moonlight presents the 359 00:21:20,480 --> 00:21:23,160 Speaker 1: same or near same results for him as seeing them 360 00:21:23,200 --> 00:21:27,600 Speaker 1: in candlelight. Lightning gives the same effect as daylight. It 361 00:21:27,680 --> 00:21:31,000 Speaker 1: doesn't matter whether the sun is rising or setting when 362 00:21:31,000 --> 00:21:34,879 Speaker 1: it comes to color, and any kind of combustible substance 363 00:21:34,960 --> 00:21:38,960 Speaker 1: creates the same color perception as any other flame. He 364 00:21:39,040 --> 00:21:41,639 Speaker 1: concludes the section of the paper with quote, my vision 365 00:21:41,680 --> 00:21:45,159 Speaker 1: has always been as it is now. His next section 366 00:21:45,359 --> 00:21:48,560 Speaker 1: breaks out the information that he's collected from other people 367 00:21:48,680 --> 00:21:51,800 Speaker 1: and their perceptions of color, starting with people he has 368 00:21:51,840 --> 00:21:54,720 Speaker 1: found who have vision that seems similar to his own, 369 00:21:55,359 --> 00:21:59,240 Speaker 1: and Dalton mentions mister Harris of Maryport and his alternate 370 00:21:59,280 --> 00:22:03,639 Speaker 1: perceptions of color. Dalton thought that, based on the description, 371 00:22:03,960 --> 00:22:07,720 Speaker 1: Harris's anomalist's vision might have been different from his own. 372 00:22:08,520 --> 00:22:11,400 Speaker 1: He discovered that one of Harris's brothers was still alive, 373 00:22:11,480 --> 00:22:15,040 Speaker 1: so he made contact and went to visit. Upon questioning 374 00:22:15,080 --> 00:22:18,320 Speaker 1: this brother and testing his vision, Dalton found that the 375 00:22:18,400 --> 00:22:21,760 Speaker 1: Harris family seemed to have the same genetic variable that 376 00:22:21,840 --> 00:22:24,520 Speaker 1: he and his brother had when it came to how 377 00:22:24,560 --> 00:22:27,400 Speaker 1: they perceived the colors of the world around them. This 378 00:22:27,520 --> 00:22:30,240 Speaker 1: led to a general line of questioning of the students 379 00:22:30,240 --> 00:22:33,480 Speaker 1: and colleagues that Dalton regularly came in contact with kind 380 00:22:33,480 --> 00:22:36,000 Speaker 1: of as a subject group, and he found a small 381 00:22:36,040 --> 00:22:39,720 Speaker 1: proportion of them shared his specific experience regarding pink and 382 00:22:39,800 --> 00:22:43,119 Speaker 1: light blue looking similar by daylight and different by candlelight. 383 00:22:44,040 --> 00:22:47,080 Speaker 1: Dalton also found just a couple of examples of people 384 00:22:47,080 --> 00:22:50,439 Speaker 1: who quote differ from the generality and from us, also 385 00:22:51,119 --> 00:22:53,359 Speaker 1: meaning that they seemed to have a different type of 386 00:22:53,400 --> 00:22:57,760 Speaker 1: color vision deficiency. He also mentioned a shared experience among 387 00:22:57,920 --> 00:23:00,560 Speaker 1: all of these people that just as with him, it 388 00:23:00,680 --> 00:23:02,880 Speaker 1: had not occurred to them that they were seeing things 389 00:23:02,920 --> 00:23:05,800 Speaker 1: differently from the majority of people, but that they too 390 00:23:05,920 --> 00:23:09,320 Speaker 1: found the names and groupings of colors perplexing at times. 391 00:23:09,640 --> 00:23:13,360 Speaker 1: Though his paper was really the beginning of science's study 392 00:23:13,400 --> 00:23:17,720 Speaker 1: of color vision deficiency, even in his really relatively small 393 00:23:17,800 --> 00:23:21,320 Speaker 1: data set, Dalton was already capturing information that showed a 394 00:23:21,359 --> 00:23:25,600 Speaker 1: difference in instances of color vision deficiency in regards to 395 00:23:25,640 --> 00:23:29,320 Speaker 1: people's sex. He noted that in the Harris family, four 396 00:23:29,359 --> 00:23:32,280 Speaker 1: of six sons in the family had what would come 397 00:23:32,320 --> 00:23:35,600 Speaker 1: to be known as color vision deficiency, sometimes also called 398 00:23:35,800 --> 00:23:40,960 Speaker 1: Daltonism for obvious reasons, but their sister didn't. Similarly, Dalton 399 00:23:40,960 --> 00:23:43,960 Speaker 1: and his brother Jonathan had the same color experience, but 400 00:23:44,119 --> 00:23:47,760 Speaker 1: their sister did not. He wrote, quote, it is remarkable 401 00:23:47,840 --> 00:23:50,320 Speaker 1: that I have not heard of one female subject to 402 00:23:50,320 --> 00:23:54,640 Speaker 1: this peculiarity. He also included the line quote, I did 403 00:23:54,640 --> 00:23:57,280 Speaker 1: not find that the parents or children in any of 404 00:23:57,320 --> 00:24:01,159 Speaker 1: these instances have been so unless in one case. So. 405 00:24:01,320 --> 00:24:04,080 Speaker 1: Even though he didn't really realize it. He was gathering 406 00:24:04,119 --> 00:24:07,520 Speaker 1: information on the recessive genetic nature of red green color 407 00:24:07,600 --> 00:24:10,880 Speaker 1: vision deficiency. Next up, we'll talk about what Dalton thought 408 00:24:10,960 --> 00:24:14,480 Speaker 1: was causing his anomalist vision, but first we will take 409 00:24:14,520 --> 00:24:25,800 Speaker 1: a break for a word from our sponsors. The third 410 00:24:25,880 --> 00:24:29,199 Speaker 1: section of Dalton's paper tries to unravel the cause of 411 00:24:29,240 --> 00:24:32,560 Speaker 1: what he was referring to as quote our anomalous vision. 412 00:24:33,640 --> 00:24:35,399 Speaker 1: One of the ways that he worked out his theory 413 00:24:35,440 --> 00:24:38,879 Speaker 1: here was to work with transparent colored liquids, and then 414 00:24:38,920 --> 00:24:41,640 Speaker 1: he would have various people look at objects through those 415 00:24:41,680 --> 00:24:45,639 Speaker 1: transparent colored liquids to record their perception of color. So 416 00:24:45,640 --> 00:24:48,040 Speaker 1: he would hold up a thing behind, like a tank 417 00:24:48,119 --> 00:24:51,879 Speaker 1: of blue water, whatever, and ask them what they saw. 418 00:24:52,080 --> 00:24:54,760 Speaker 1: And because people with you know, quote unquote normal vision 419 00:24:54,880 --> 00:24:58,560 Speaker 1: described color similar to what he saw in his normal 420 00:24:58,680 --> 00:25:02,120 Speaker 1: day to day life when they looked through a tank 421 00:25:02,160 --> 00:25:05,600 Speaker 1: of blue water, he came to this incorrect conclusion that 422 00:25:05,720 --> 00:25:08,800 Speaker 1: quote one of the humors of my eye must be 423 00:25:08,840 --> 00:25:13,360 Speaker 1: a transparent but colored medium, so constituted as to absorb 424 00:25:13,480 --> 00:25:17,160 Speaker 1: red and green rays principally because I obtain no proper 425 00:25:17,160 --> 00:25:20,879 Speaker 1: idea of these in the solar spectrum, and to transmit 426 00:25:21,040 --> 00:25:25,040 Speaker 1: blue and other colors more perfectly. Honestly, this is a 427 00:25:25,119 --> 00:25:32,600 Speaker 1: totally reasonable conclusion based on understanding rates. He outlined how 428 00:25:32,600 --> 00:25:35,640 Speaker 1: this would impact the perception of various colors, and then 429 00:25:35,680 --> 00:25:39,280 Speaker 1: addressed why the colors changed so drastically for him and 430 00:25:39,720 --> 00:25:42,760 Speaker 1: others like him in candle light, writing quote, when any 431 00:25:42,840 --> 00:25:45,840 Speaker 1: kind of light is less abundant in blue, as is 432 00:25:45,880 --> 00:25:50,119 Speaker 1: the case with candlelight compared to daylight, our eyes serve 433 00:25:50,400 --> 00:25:53,439 Speaker 1: in some degree to temper that light so as to 434 00:25:53,520 --> 00:25:57,840 Speaker 1: reduce it nearly to the common standard. The Earth's atmosphere, 435 00:25:57,920 --> 00:26:01,479 Speaker 1: he believed, was a blue fluid that quote, modifies the 436 00:26:01,480 --> 00:26:06,320 Speaker 1: Sun's light so as to occasion the commonly perceived difference. 437 00:26:07,160 --> 00:26:10,040 Speaker 1: So this paper was met with some curiosity, and his 438 00:26:10,280 --> 00:26:13,320 Speaker 1: very detailed comparisons of his vision to that of other 439 00:26:13,359 --> 00:26:16,760 Speaker 1: people who saw color normally offered a lot of insights. 440 00:26:17,400 --> 00:26:19,960 Speaker 1: But this idea of a blue humor in his eye 441 00:26:19,960 --> 00:26:22,800 Speaker 1: that was causing his anomalous color vision was kind of 442 00:26:22,840 --> 00:26:27,120 Speaker 1: dismissed by the scientific community, and in response, Dalton, who 443 00:26:27,160 --> 00:26:29,800 Speaker 1: really thought he was onto something with it, donated his 444 00:26:29,840 --> 00:26:33,760 Speaker 1: eyes to science. He wrote up a document that requested 445 00:26:33,840 --> 00:26:37,080 Speaker 1: that his eyes be dissected upon his death to see 446 00:26:37,080 --> 00:26:39,560 Speaker 1: if he had been correct and whether there was any 447 00:26:39,560 --> 00:26:42,480 Speaker 1: other physical evidence to explain the way he perceived color. 448 00:26:43,160 --> 00:26:46,000 Speaker 1: A little less than a decade after Dalton's writing on 449 00:26:46,080 --> 00:26:51,080 Speaker 1: his anomalous vision, scientist Thomas Young published on the theory 450 00:26:51,160 --> 00:26:54,199 Speaker 1: of light and colors, and this put forth the idea 451 00:26:54,200 --> 00:26:57,159 Speaker 1: that there were receptors in the eye for each of 452 00:26:57,200 --> 00:27:00,760 Speaker 1: the colors red, green, and blue. So he was totally 453 00:27:00,800 --> 00:27:04,880 Speaker 1: onto it. And Young addressed Dalton's work and his anomalous 454 00:27:04,880 --> 00:27:07,919 Speaker 1: color vision with a different theory that there was a 455 00:27:08,040 --> 00:27:11,760 Speaker 1: quote absence or paralysis of those fibers of the retina 456 00:27:11,880 --> 00:27:16,360 Speaker 1: which are calculated to perceive read. He was so completely 457 00:27:16,400 --> 00:27:19,159 Speaker 1: on the right track that you would think that this 458 00:27:19,240 --> 00:27:22,280 Speaker 1: would have just broken eye science wide open. But no, no, 459 00:27:22,400 --> 00:27:26,400 Speaker 1: it advancement slowed down after this and studying the eye, 460 00:27:26,480 --> 00:27:28,760 Speaker 1: and that went on for decades. Yeah, I was like 461 00:27:28,840 --> 00:27:30,920 Speaker 1: people were like neat idea, and they moved on to 462 00:27:31,000 --> 00:27:35,760 Speaker 1: other stuff beyond the study of color vision deficiency. John Dalton, 463 00:27:35,840 --> 00:27:39,560 Speaker 1: of course, continued to make important contributions to the scientific 464 00:27:39,680 --> 00:27:43,600 Speaker 1: world concurrently while working on figuring out why he couldn't 465 00:27:43,600 --> 00:27:46,320 Speaker 1: see flowers the same way as other people. He also 466 00:27:46,359 --> 00:27:51,200 Speaker 1: published a work titled Meteorological Observation and Essays. He published 467 00:27:51,200 --> 00:27:54,320 Speaker 1: additional work in meteorology as well, and his work in 468 00:27:54,359 --> 00:27:57,560 Speaker 1: this field led to some fellow scientists considering him the 469 00:27:57,640 --> 00:28:01,680 Speaker 1: father of meteorology, although his work anytime somebody gets called 470 00:28:01,680 --> 00:28:03,960 Speaker 1: the father of something, I always have to go eh, 471 00:28:04,000 --> 00:28:06,159 Speaker 1: because his work was of course building on that of 472 00:28:06,200 --> 00:28:08,560 Speaker 1: his mentors on this subject. He had particularly had a 473 00:28:08,600 --> 00:28:12,760 Speaker 1: really good mentor in meteorology when he was studying as 474 00:28:12,800 --> 00:28:17,240 Speaker 1: a teacher. Dalton also did a lot of work in chemistry, 475 00:28:17,520 --> 00:28:21,600 Speaker 1: specifically atomic theory. His work in this area came to 476 00:28:21,680 --> 00:28:25,600 Speaker 1: some incorrect conclusions, but it was also instrumental in moving 477 00:28:25,640 --> 00:28:29,240 Speaker 1: the scientific community away from the long held idea that 478 00:28:29,359 --> 00:28:33,359 Speaker 1: matter was, at the basic level all the same and 479 00:28:33,440 --> 00:28:38,240 Speaker 1: just configure differently to form different things. Dalton championed the 480 00:28:38,280 --> 00:28:40,760 Speaker 1: idea that there were all kinds of different atoms with 481 00:28:40,800 --> 00:28:44,560 Speaker 1: different sizes and weights, and that they behaved differently. He 482 00:28:44,600 --> 00:28:47,560 Speaker 1: started a project to measure the masses of different atomic 483 00:28:47,600 --> 00:28:51,040 Speaker 1: particles to begin cataloging all of the different atoms that 484 00:28:51,040 --> 00:28:54,400 Speaker 1: could be found. He presented the first table of atomic 485 00:28:54,440 --> 00:28:56,800 Speaker 1: weights in eighteen oh three, and his work in this 486 00:28:56,920 --> 00:29:00,640 Speaker 1: area propelled organic chemistry forward. He is also sometimes called 487 00:29:00,640 --> 00:29:05,080 Speaker 1: the father of chemistry. Dalton had joined the Manchester Literary 488 00:29:05,120 --> 00:29:08,440 Speaker 1: and Philosophical Society in seventeen ninety three when he was 489 00:29:08,480 --> 00:29:12,000 Speaker 1: still in his twenties. In eighteen seventeen, as a man 490 00:29:12,080 --> 00:29:15,800 Speaker 1: in his early fifties, he became its president. He held 491 00:29:15,800 --> 00:29:18,200 Speaker 1: this position for the rest of his life. His scientific 492 00:29:18,280 --> 00:29:21,600 Speaker 1: career slowed down quite a bit. Yeah, there were some 493 00:29:21,680 --> 00:29:24,880 Speaker 1: other issues where he had some papers that were denied 494 00:29:24,880 --> 00:29:28,320 Speaker 1: for publication, and it just wasn't like the heyday he 495 00:29:28,360 --> 00:29:30,680 Speaker 1: had when he was a little younger. He had the 496 00:29:30,760 --> 00:29:34,160 Speaker 1: unique distinction though, of seeing, for example, his own statue 497 00:29:34,200 --> 00:29:37,960 Speaker 1: erected in Manchester during his lifetime for his accomplishments. And 498 00:29:38,480 --> 00:29:41,200 Speaker 1: while he had been barred from an education at Oxford 499 00:29:41,280 --> 00:29:43,240 Speaker 1: or Cambridge as a young man because he was a 500 00:29:43,280 --> 00:29:47,680 Speaker 1: Quaker not an Anglican, he received honorary degrees from both 501 00:29:47,760 --> 00:29:50,840 Speaker 1: later in life. He also served as a foreign Associate 502 00:29:50,840 --> 00:29:54,680 Speaker 1: of the French Academy of Sciences. On April eighteenth, eighteen 503 00:29:54,760 --> 00:29:58,280 Speaker 1: thirty seven, Dalton, who was seventy at the time, had 504 00:29:58,280 --> 00:30:01,720 Speaker 1: a stroke that resulted in a part paralysis, and then 505 00:30:01,720 --> 00:30:05,280 Speaker 1: he had another small stroke or possibly a seizure several 506 00:30:05,320 --> 00:30:09,120 Speaker 1: days later. Being pretty pragmatic, he set his affairs in 507 00:30:09,400 --> 00:30:11,720 Speaker 1: order as soon as he was recovered enough to do so. 508 00:30:11,760 --> 00:30:15,200 Speaker 1: But then he lived another seven years. He continued as 509 00:30:15,240 --> 00:30:19,160 Speaker 1: president of the Literary and Philosophical Society. He made visits 510 00:30:19,160 --> 00:30:22,200 Speaker 1: to Lake Country. That's something that he had been doing 511 00:30:22,320 --> 00:30:24,800 Speaker 1: throughout his life. Yeah, it was a very close call, 512 00:30:24,840 --> 00:30:26,880 Speaker 1: and then he kind of was like, well, I'm still alive. 513 00:30:26,920 --> 00:30:30,320 Speaker 1: I'm going to keep doing my living stuff. John Dalton 514 00:30:30,360 --> 00:30:34,160 Speaker 1: died finally on July twenty seventh, eighteen forty four. He 515 00:30:34,400 --> 00:30:37,160 Speaker 1: was really really beloved in Manchester by this point, and 516 00:30:37,200 --> 00:30:39,360 Speaker 1: he was given a public funeral by the city on 517 00:30:39,400 --> 00:30:43,640 Speaker 1: August twelfth, eighteen forty four, and estimated forty thousand people 518 00:30:43,720 --> 00:30:47,040 Speaker 1: paid their respects before Dalton was interred. The day after 519 00:30:47,120 --> 00:30:50,600 Speaker 1: Dalton's death, on July twenty eighth, eighteen forty four, his 520 00:30:50,720 --> 00:30:54,520 Speaker 1: wishes were carried out. His eyes were dissected. This was 521 00:30:54,560 --> 00:30:58,560 Speaker 1: done by doctor Joseph Bransom to determine whether this idea 522 00:30:58,640 --> 00:31:01,680 Speaker 1: about having a blue humor and his eye was correct. 523 00:31:01,720 --> 00:31:05,840 Speaker 1: Of course it was not. Ransom described what he found 524 00:31:05,840 --> 00:31:10,640 Speaker 1: in Dalton's eye as quote perfectly pellucid. Ransom also sliced 525 00:31:10,680 --> 00:31:13,600 Speaker 1: off a section of the posterior pull of the eye 526 00:31:14,080 --> 00:31:16,520 Speaker 1: and used it as a lens to see if colors 527 00:31:16,560 --> 00:31:19,000 Speaker 1: that were viewed through it, especially red and green, took 528 00:31:19,040 --> 00:31:22,040 Speaker 1: on a different hue, which they did not. But Dalton's 529 00:31:22,040 --> 00:31:24,800 Speaker 1: eyes were not discarded after that, so for clarity he 530 00:31:24,880 --> 00:31:27,400 Speaker 1: did the full dissection on one eye. That little part 531 00:31:27,440 --> 00:31:30,680 Speaker 1: he sliced off was from the second eye, so he 532 00:31:30,760 --> 00:31:34,360 Speaker 1: had only taken the primary samples from one. The other 533 00:31:34,520 --> 00:31:37,720 Speaker 1: was mostly intact, and the remains of Dalton's eyes were 534 00:31:37,720 --> 00:31:40,400 Speaker 1: preserved and were eventually given to the Manchester Literary and 535 00:31:40,400 --> 00:31:43,880 Speaker 1: Philosophical Society. That was not the end of their story. 536 00:31:44,800 --> 00:31:47,720 Speaker 1: One hundred years after Dalton died in nineteen ninety five, 537 00:31:48,200 --> 00:31:52,320 Speaker 1: a DNA analysis was conducted on his preserved eyes, and 538 00:31:52,400 --> 00:31:56,840 Speaker 1: this examination determined that he had deuterinopia, conclusively proving that 539 00:31:56,920 --> 00:32:00,320 Speaker 1: he had red green color vision deficiency. Two years after 540 00:32:00,320 --> 00:32:03,640 Speaker 1: those findings were published, in nineteen ninety seven, the eyes 541 00:32:03,680 --> 00:32:07,040 Speaker 1: were donated to the Science and Industry Museum in Manchester 542 00:32:07,440 --> 00:32:10,400 Speaker 1: and they remained in the collection there to this day. YEP, 543 00:32:10,440 --> 00:32:15,120 Speaker 1: you can find pictures of them online in the eighteen seventies, 544 00:32:15,240 --> 00:32:18,960 Speaker 1: German anatomis Max Schultz identified the rods and cones of 545 00:32:19,000 --> 00:32:22,000 Speaker 1: the retina and deduced that rods were dedicated to night 546 00:32:22,080 --> 00:32:25,400 Speaker 1: vision and cones to daylight vision. Then later in the 547 00:32:25,440 --> 00:32:29,120 Speaker 1: eighteen seventies, Wilhelm Cune laid the groundwork for a concept 548 00:32:29,240 --> 00:32:33,440 Speaker 1: of photochemical basis for vision. In the eighteen nineties, Spanish 549 00:32:33,520 --> 00:32:39,080 Speaker 1: neuroscientist Santiago Ramoni Cajel studied the retina and drew detailed 550 00:32:39,120 --> 00:32:43,080 Speaker 1: diagrams of the cells within it. Cahl's scientific drawings are 551 00:32:43,160 --> 00:32:46,280 Speaker 1: incredibly intricate and very beautiful, and they were part of 552 00:32:46,320 --> 00:32:50,520 Speaker 1: an art exhibit at NYU in twenty eighteen. Yeah, so, 553 00:32:51,280 --> 00:32:54,040 Speaker 1: you know, all of the things that would have explained 554 00:32:54,040 --> 00:32:56,320 Speaker 1: to Dalton what was going on came a little too late. 555 00:32:56,760 --> 00:32:59,680 Speaker 1: There was also a cool discovery in nineteen ninety one. 556 00:32:59,680 --> 00:33:03,800 Speaker 1: So recently a new kind of photoreceptor was discovered, the 557 00:33:03,880 --> 00:33:07,200 Speaker 1: ganglion cell, and that once again refined our knowledge of 558 00:33:07,200 --> 00:33:10,480 Speaker 1: how the human eye takes in and processes visual information. 559 00:33:11,680 --> 00:33:20,800 Speaker 1: Always learning. I really, really really love John Dalton's story, 560 00:33:20,920 --> 00:33:24,320 Speaker 1: and I love this part of it. I knew a 561 00:33:24,320 --> 00:33:27,920 Speaker 1: little bit more about, you know, his work in establishing 562 00:33:27,960 --> 00:33:29,960 Speaker 1: the basis of a lot of the chemistry we use. 563 00:33:30,680 --> 00:33:33,240 Speaker 1: But I didn't. I had never read this paper before, 564 00:33:33,280 --> 00:33:44,320 Speaker 1: and I honestly it's the most fun read. Thanks so 565 00:33:44,400 --> 00:33:47,240 Speaker 1: much for joining us on this Saturday. If you'd like 566 00:33:47,280 --> 00:33:50,320 Speaker 1: to send us a note, our email addresses History Podcast 567 00:33:50,440 --> 00:33:54,080 Speaker 1: at iHeartRadio dot com, and you can subscribe to the 568 00:33:54,120 --> 00:33:57,480 Speaker 1: show on the iHeartRadio app, Apple Podcasts, or wherever you 569 00:33:57,560 --> 00:34:04,440 Speaker 1: listen to your favorite shows.