USE OF THE SLIDE RULE.

King Country Chronicle, Volume VII, Issue 560, 19 April 1913, Page 2

USE OF THE SLIDE RULE.

It is a very remarkable thing that though the slide rule was invented bv an Englishman more than 250 years ago it is almost unknown outside the ranks of engineers and students of physical science. It deserves to be better known ; in fact, I consider it to be a disgrace that we are not all taught its use. Only • those who have used it know what an enormous saving of time and worry it is to anyone who has 1o deal* with figures. By its use the "rule of three" becomes simply a case of setting the slide rule and reading off the answer; feet can at once be converted into metres ; francs into pounds sterling, a motorist can at once calculate the horsepower of his motor, whether the diameter of his cylinder is given in inches or millimetres, or he can convert the seconds taken to pass through a police trap into miles per hour; given the rate of wages for a year the wages for :i week or a month can be read off at once; one can calculate interest on capital and questions relating to buying and selling of stocks and shares: the square or square root of a number can be read off at once, and multiplication and division are done in the twinkling of an eye. In fart, the uses of this instrument are endless, but like many* other useful things its use is not taught in our schools and Universities, except in the science and engineering schools. There is no reason why anyone who understands arithmetic should ;v ••. be able to use the slide rule, no high mathematics are needed; at one time they used to be made as part of a carpenter's rule and the only reason why carpenters should r.ot generally use them is that like others they have not been taught how to do so. They can be bought for a few shillings; I believe that some are now made in cardboard and cost about eighteenpence. . If schoolmasters would include instruction on the use of the slide rule in elementary mathematical classes they would be conferring a real boon on their pupils, and I fancy the latter, fresh from the tedium of the rule of three, would not be slow to take advantage of it.