Fowler's Adding Machine

On 14th of July, 1863, George B. Fowler of Chicago, Illinois, was granted his first patent (No 39222) for an adding machine. In 1890 Fowler received a second patent (No 432266) for improved version of his device.

In 1860s the machine was advertised as the only practical and reliable adding machine in the world :-), and was reported to be on market since 1869, produced by the company of its inventor—Geo. B. Fowler & Co., Chicago, IL (see the lower photo). Later on Fowler moved to New York and founded a new company—Fowler Adding Machine Co., New York, which produced the device. When launched to the market, the device cost $5. In 1890s the device was sold by the Universal Adding Machine Co., for $8, under the name Universal Adding Machine.

Fowler's adding machine

The machine (see the lower drawing from the first patent) was a slide bar adder, operated by pin or pencil. The upper slide represents the units, the next the tens, etc. If it desired to add two numbers, for instance 251 and 185, the pin is inserted into the hole opposite the figure 1 on the first slide, and said slide is pushed toward the right until the pin strikes the cap D'. Then the pin is inserted into the hole opposite the figure 5 on the second slide, and so on for all digits of the addends. If the hole is on the dark portion of the slide, then the said slide has to be moved leftward, instead of rightward. The result of operation is ascertained by turning the platform A upside down and noticing the figures appearing on the under side of the slides opposite to the apertures b in the platform.

The patent drawing of Fowler's Adder