Calcuator forensics history question

[paul0207]

(04-24-2021 06:31 AM)Benjer Wrote:  I think British Thornton tried to address this issue by including "differential trig" scales on some of their slide rules. They allowed you to compute the sine of angles very close to 90 (or cosine of angles close to 0) with a wee bit more accuracy than typical trig scales.

Another way to compare is to note that on a typical 10" slide rule, the physical distance between sin 80 and sin 90 is about 1/16th of an inch, while on the 10" British Thornton the distance between the same two values on its differential trig scale is about 7/16th of an inch, which provides quite a bit more room for divining values.

Thanks for the info.
I found this article by the Oughtred Society that mentions the "differential scales" used by British Thornton and the "evenly spaced scales" by Australian W&G slide rules:
https://osgalleries.org/journal/pdf_file...9.1P33.pdf