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From: brian@advsys.UUCP (Brian Rippon)
Newsgroups: comp.lang.postscript
Subject: Oh, what's the point? (was points and rulers)
Message-ID: <563@purdey.advsys.UUCP>
Date: 17 Jan 90 13:14:26 GMT
References: <50949@bbn.COM>
Reply-To: brian@advent.co.uk (Brian Rippon)
Organization: Advent Systems Ltd., Wokingham, England
Lines: 27

In article <50949@bbn.COM> news@bbn.COM (News system owner ID) writes:
>The "conventional American" point IS kind-of metricized: The 1886
>standard from the United States Type Founders' Association was based on
>the observation that the American-pica had an almost-relationship to
>the cm:
>
>     83 picas ~= 35 cm
>
>and so they standardized on exactly "83 picas = 35 cm". 

Well, I'm confused. How big was a centimetre in the US in those days?
Since SI, there are 2.54 cm/inch, so you would get 72.2811428571... points/inch.

Now to quote Stephenson Blake & Co. Ltd (1915),
	"In 1886 the United States Type Founder's Association adopted
	the present American Point Standard, taking as their unit a
	pica measuring .166044 inch divided into twelve equal parts
	which were called points. The American point (sic) therefore
	measures .013837 inch. The above figures are given on the
	authority of the American Type Founders' Co."

If that was right, you get 72.270000722700007227... points/inch.

That given, it's all an approximation, and 72 sounds as good a number
as any other. Fournier and Adobe chose well.

Brian.