WEBVTT - How do nail penny measurements work? 0:00:00.600 --> 0:00:03.560 Welcome to brain Stuff from how stuff works dot com, 0:00:03.680 --> 0:00:14.480 where smart happens the high on Marshall Brain with today's question, 0:00:14.800 --> 0:00:19.159 can you explain the diameter measurements used in nails? You 0:00:19.200 --> 0:00:23.000 can buy nails ranging from twopenny up to sixtypenny in 0:00:23.040 --> 0:00:27.880 the United States, represented as two D or sixty D, respectively. 0:00:28.400 --> 0:00:31.120 When you buy a twopenny nail, what you're buying is 0:00:31.160 --> 0:00:34.600 a nail that is an inch long. A threepenny nail 0:00:34.760 --> 0:00:36.959 is an inch, and a quarter fourpenny is an inch 0:00:37.000 --> 0:00:40.400 and a half, and so on, increasing by quarter inches. 0:00:40.880 --> 0:00:44.400 That works up to a twelvepenny nail. So a twelvepenny 0:00:44.479 --> 0:00:47.559 nail is three and a quarter inches long, a sixteenpenny 0:00:47.640 --> 0:00:50.360 nail is three and a half inches long, a twenty 0:00:50.400 --> 0:00:55.160 penny is four inches, and after that there's the thirty, forty, fifty, 0:00:55.160 --> 0:00:58.440 and sixtypenny nails, each one a half inch longer than 0:00:58.480 --> 0:01:02.320 the last, So a sixty penny nail is six inches long. 0:01:03.040 --> 0:01:07.040 Why is D used instead of P when talking about 0:01:07.240 --> 0:01:10.920 pennies and nails? For example, a two D nail is 0:01:11.040 --> 0:01:15.280 a twopenny nail. It probably comes from the Roman coin 0:01:15.360 --> 0:01:19.080 called the denarius. It's not clear that anyone knows where 0:01:19.080 --> 0:01:22.600 the penny designation comes from, though it might have indicated 0:01:22.640 --> 0:01:24.960 the cost of a hundred nails of a given size 0:01:25.000 --> 0:01:29.000 in the four hundreds, but who knows. For more on 0:01:29.080 --> 0:01:31.520 this and thousands of other topics, is it how stuff 0:01:31.520 --> 0:01:36.319 works dot com