Page:St. Nicholas, vol. 40.1 (1912-1913).djvu/106

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74
NATURE AND SCIENCE FOR YOUNG FOLKS
[Nov.,

watch is approximately 192-10,000,000,000 horse-power.” One hundred and ninety-two ten-billionths of one-horse power! The distance traveled is enormously great, the power needed is enormously small, if I may be allowed to use such an expression, and one’s astonishment is increased when he remembers that a single horse-power is the power to lift 33,000 pounds one foot in one minute.

A copy of the item from the London publication was also sent to the Waltham Watch Company of Waltham, Massachusetts. Mr. E. A. Marsh, of that company, adds the following even more astonishing facts as to the accurate work done by a watch:

“In addition to the above it ought to be said that, however astonishing the statements as to the enormous amount of work which is performed by the pocket watch, the truly remarkable feature concerning it is the marvelous accuracy with which that work is done. The following brief statements will help to show how wonderfully accurate the work of a running watch really is:

“In nearly all modern watches the mechanism is so designed that, in order to obtain accurate ‘mean sun time’, the balance-wheel must vibrate exactly eighteen thousand times (18,000) every hour. We say ‘exactly eighteen thousand’, for if there should be one vibration in each hour less than the required number, the watch would lose two and two fifths minutes in a month. Such an error would be serious.”

An interesting comparison may be made in this way: in a No. 16 watch (the ordinary size for men), the balance-wheel makes about one and one quarter turns for each vibration, and its rim, in each vibration, will travel two and three quarters inches. In a single day this will amount to rather more than sixteen and one half (16.61) miles, or farther than most persons care to walk in a day.

If you planned to walk exactly the 16.61 miles, and should fall short of that distance by only ten feet, or by only about five steps, it would be a trifling matter; but if the watch balance should make a similar failure, it might become serious in its results, for the watch would then lose nine and four fifths seconds a day, or four and nine tenths minutes a month. A watch that kept no better time than that would be exceedingly unsatisfactory.

Wonderful as are the achievements of a watch, it is still more wonderful that man has been able to invent machinery of such marvelous delicacy, that, when set in operation, it will automatically manufacture the microscopic parts required.

The Pygmy Hippopotamus

By permission of the New York Zoölogical Society.

The New York Zoölogical Park has recently obtained a pair of the rare and strange pygmy hippopotamuses (Chæropsis liberiensis) recently obtained in Africa. Director Hornaday thus describes them:

“This adult male is thirty inches high at the shoulders, seventy inches in-length from end of nose to base of tail, and the tail itself is twelve inches long. The weight of this animal is four hundred and nineteen pounds. All these figures are offered subject to correction.

“The female is believed to be only two years old. It stands eighteen inches high at the shoulders, and weighs one hundred and seventy-six pounds.

“The pygmy hippo is characterized first of all by its midget size, which, in the adult animal, is about equal to that of a twelve-months-old baby

By permission of the New York Zoölogical Society.
A Pygmy Elephant.