Collection of pages from K&E catalogs for the 4140 and 4141

Hudson's Horsepower Computing Scale


Page from the 1910 catalog

The Hudson's Horsepower Computing Scale is 4 1/2" long. It has two slides. Its purpose is in various calculations for steam engines. It was offered in a cardboard and boxwood versions.

Model numbers in the group:


The 4140 and 4141 were first shown in the 1901 catalog. The last mention of the 4140 and 4141 is in the 1916 catalog. The following is a brief history of the Hudson's Horsepower Computing Scale as is told in the K&E catalogs that are available at this time. Exact timing is not possible because of the time between catalogs.

Links to catalog pages for the 4140 and 4141 family of slide rules:

Scans: Link to scans of 4141s