Artifact Details



Catalog Number



Physical object




Monroe Calculating Machine Company

Place Manufactured



This record was created de novo. D.S. 10/8/98. Donor text: I believe it to be the largest electric rotary mechanical calculator ever built as a standard commercial product. It will multiply 13 digits by 13 digits with 26 places in the result. It has an extra accumulating dial for multipliers. It was bought about 1932 at which time we were computing and publishing extremely large tables of bond values, showing for a given coupon rate, yield rate and term, the value with nine significant digits, or to the nearest penny on one million dollars. The 13 places were very important in consecutive calculation of value while maintaining extra protective decimal places. Later is was used for "Financial Compound Interest and Annuity Tables" on units carrying 10 decimals, and which might grow to many digits to the left of the decimal point. Indeed we used this Monroe carrying extra digits in the air beyond the capacity of the machine, since the left-hand digits were easily verifiable. Indeed, it was not replaced until the IBM 602A, still mechanical and slow, but capable of multiplying about 30 digits by 30 digits if you had the patience to wait for it to accomplish the job. I will supply a 602A manual in case your historical interest is super strong. I also enclose my file of "Mathematical Tables and Aids to Computation" with perhaps a few missing. It will serve to emphasize the amazing progress in a very few years. And I include a manual of the Mark I at Harvard as an instance of triumphant but misdirected energy. I hope they will give someone amusement--but I noticed badly frayed wires, and I hope you will re-wire the plug before inserting it for power. Truly, Charles H. Gushee, Chairman of the Board Financial Publishing Company


Calculator: electromechanical

Lot Number