In 1879 a man named “F. E. Marsh” began modifying ordinary Stanley No. 62 ˝ four fold rules with gradations on the brass bindings of his own creation that allowed the user of he rule to measure the depth and diameter of canisters which would then be converted in the dry measure capacities of the canisters (pint, quart, etc). Marsh made instructions for the use of this rule (Marsh's Patent Dry Measure Rule”, and pasteboard boxes to hold the rule. Today these variants are scarce and command prices of several hundreds of dollars. They were produced between 1879 and 1921. A patent was never awarded for this invention. The reason for the failure to patent the idea may have been because an English rule for used calculations that were devised by the British Astronomer Royal, George Biddell Airy. “Airy's Dry Measure Gauge” was used as a standard in England for checking dry goods measures in grocery and other stores. Airy's original gage was a brass strip 22 inches long, and was graduated in a fashion that produced a result, that when the depth and diameter of a canister were multiplied, was read from a table on the rule to find the volume of the measure.
Airy's rule was used beginning in 1890, but the English Board of Trade's regulations were changed in 1907 and dry goods were sold by weight rather than volume. Airy's rule then fell into disuse and it is a rare one to find today. Apparently Marsh's rule used a similar mathematics, the theory of which had been developed by Airy.
Sometime around 1912 the folks at L. & W.E. Gurley in Troy, NY revived the idea of using Airy's calculated gradations on a boxwood rule, and seem to have contracted with Stanley to produce it on the frame of a No. 54 boxwood rule. This included both the table of resultant values (as on the original Airy rule), and also the note: “Pat. Applied For” --but none seems to have been forthcoming. The rule is somewhat faded, but the gradations and results table are clear. The rule with confirm the volumes of canisters with volumes equal to ˝ pint, 1 pint, 1 quart, 2 quarts, 4 quarts, 1 peck, ˝ bushel, and 1 bushel. It is a collectible rule in collectible condition. Easily Good+
