The largest adding machine ever made was produced in 1915 and has a capacity of forty columns, or within one unit of ten duodecillions. This is a number too prodigious for the mind of man to grasp. This machine was exhibited at the Panama Expositions in 1915.

To get an idea of the capacity of this machine, suppose that your income is $1,000,000 a second. At this rate for twenty-four hours a day, with no stops for eating or sleeping, it would take you 352,331,022,041,828,731,333,333,333, years to accumulate a duodecillion dollars. All the hairs on the heads of all human beings, which are supposed to be numberless, are only a small fraction of a duodecillion.

This machine has a practical use in adding several sums simultaneously, and takes the place of from ten to a dozen smaller machines.

Adding machines are made that figure in English pence, shillings and pounds; in Japanese yen, and in the monetary system of most civilized countries. They will change inches into feet, pounds into bushels, and do other "stunts" that would make the average schoolboy envious when it comes to arithmetic.

The most complicated problems of multiplication, division and fractions may be handled with ease on these machines. They have taken a great part in the day's work of modern business, and it would be hard to imagine how the world's finance and industry could be handled without them. Adding and calculating machines have become almost as necessary in modern business as the telephone and the typewriter.