Patent Model for Simplex Slide Rule Clasp Invented by Rudolph C. Smith

Smith, Rudolph C. · 1887

This ten-inch, linear one-sided slide rule has scales on the base labeled 3 and 2. On one side of the slide, scales are labeled 4 and 1. On the other side are scales labeled S and T and a scale of equal parts, which divides each inch into 50 increments. The 4, 1, and 2 scales are identical, divided logarithmically from 1 to 10 twice (like the A and B scales on a Mannheim slide rule). The 3 scale is graduated logarithmically once from 1 to 10 (like the C and D scales on a Mannheim rule, although the numbers on this scale are marked with superscript 2s; i.e. 2²).