To those not familiar with the technical features of the key-driven calculating machine Art, it would seem that if a machine could be made to add one column of digits, it would require no great invention or ingenuity to arrange such mechanisms in a plurality of orders. But the impossibility of effecting such a combination without exercising a high degree of invention will become evident as the reader becomes familiar with the requirements, which are best illustrated through the errors made by those who tried to produce such a machine.
As stated, the first authentic knowledge we have of an actual machine for adding is extant in models made by Pascal in 1642, which were all multiple-order machines, and the same in general as that shown in the [illustration, page 10].
Calculating machines in use abroad for centuries
History shows that Europe and other foreign countries have been using calculating machines for centuries. Like that of Pascal’s, they were all multiple-order machines, and, although not key-driven, they were capable of adding a number of columns or items of six to eight places at once without the extra manipulation described as necessary with single-order digit adding machines. A number of such machines were made in the United States prior to the first practical multiple-order key-driven calculator.
First key-driven machines no improvement to the Art
This fact and the fact that the only operative key-driven machines made prior to 1887 were single-digit adders are significant proof that the backward step from such multiple-order machines to a single-order key-driven machine was from the lack of some unknown mechanical functions that would make a multiple-order key-driven calculator possible. There was a reason, and a good one, that kept the inventors of these single-order key-driven machines from turning their invention into a multiple-order key-driven machine.
It is folly to think that all these inventors never had the thought or wish to produce such a machine. It is more reasonable to believe there was not one of them who did not have the wish and who did not give deep thought to the subject. There is every reason to believe that some of them tried it, but there is no doubt that if they did it was a failure, or there would be evidence of it in some form.
The Hill Machine
The U. S. Patent Office records show that one ambitious inventor, Thomas Hill, in 1857 secured a patent on a multiple-order key-driven calculating machine ([see illustration]), which he claimed as a new and useful invention. The Hill patent, however, was the only one of that class issued, until the first really operative modern machine was made thirty years later, and affords a fine example by which the features that were lacking in the make-up of a really operative machine of this type may be brought out.
Description of the Hill machine