. The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world. rfares, the cyclometer, odometer, and cash-register are all simple forms of calculatingmachines, based on the principle common tonearly all these machines, namely, the use of a•disk or wheel bearing figures from o to 9 inclu-sive. A very simple form is shown in the illus-tration. When the disk at the right has com-pleted one revolution it advances the centre diskone step ; and so on successively at each revo-lution of the right-hand disk unt
. The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world. rfares, the cyclometer, odometer, and cash-register are all simple forms of calculatingmachines, based on the principle common tonearly all these machines, namely, the use of a•disk or wheel bearing figures from o to 9 inclu-sive. A very simple form is shown in the illus-tration. When the disk at the right has com-pleted one revolution it advances the centre diskone step ; and so on successively at each revo-lution of the right-hand disk until after 10 revo-lutions the centre disk has likewise completeda full revolution, when it in turn advances theleft-hand disk one step and thus registers train of disks may be extended to registerany number desired. Apertures in the casingof the train enable the figures to be read. During recent years the keyboard type ofcalculating machine has come into extended usein banks, business houses, and other concernswhere numerous and tedious calculations haveto be made. There are a number of thesemachines, but that of Dorr E. Felt of Chicago is. Wheels of a form of counter, illustrating the principlecommon to nearly all calculating machines. perhaps the best known. This was introduced in1889, and has been improved several times, the•different styles being known as the compto-graph and comptometer. The comptograph isthe more complete machine of the two, andprints the record of its work as performed. Thecomptometer is very similar, but docs not printits record, and hence cannot be used for machine performs any of the four arith-metical operations of adding, subtracting, multi-plying, and dividing, besides extracting thesquare root. In the comptograph the totals arerecorded in front of the operator, and. if, byaccident, wrong keys have been struck, they canbe instantly released by touching a release key,after which the correct keys can be struck. The keys rese
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectencyclo, bookyear1908
