Page:Popular Science Monthly Volume 53.djvu/587

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569
FRAGMENTS OF SCIENCE.

est month is January, 31.4°, and the warmest August, 54.9°. Every year it is either rainy or snowy two hundred days on an average. The annual rainfall is very great, being eighty-one inches. Point Barrow, the extreme northern point of Alaska, is in 71° 23' north, 156° 40' west, and its climate is that of the coast line of the whole timber or moorland region situated along the Arctic Ocean. The winter is long, freezing weather lasting from early September to early June. The mean winter temperatures are December, -15.4°, January, -17.5°, and February, -18.6°, with occasional periods when the cold is from 40° to 52° below zero. The average heat of July is 38.1°, but the temperature often rises above 50°, and has touched 65.5°. The snowfall is light. The severity of the cold is indicated by the fact that the ground was found frozen as far as excavations were made (thirty-eight feet). Temperature observations at Dawson, in the Klondike region, during the fifteen months from August, 1895, to November, 1896, show the following records: In July only the temperature did not sink below freezing. During June, July, and August, 1896, the temperature rose on twenty-nine days above 70° and thrice above 80°. The extreme severity of the winter is indicated by the fact that from December 1, 1895, to February 1, 1896, the temperature fell below zero every day. On twenty-eight days it fell lower than -40°, on fourteen days lower than -50°, and on nine days lower than -60°. The average temperature for January, 1896, was -40.7°, and for February -35.4°. Bright weather is the rule. The Yukon River broke up on May 17th. It was frozen solid November 25th.

 

The Holophane Globe.—The results of an inquiry by a committee of the Franklin Institute into the efficiency of Blondel and Psaroudaki's holophane globes are printed in that body's journal for April. The object of the holophane globe is "to secure diffusion of the light, as well as such a form of distribution that the light usually lost by being Bent off into space above the source of light shall be distributed below that plane and thus made useful." In the globes under consideration the interior surface is made of a continuous series of vertical flutings. The function of these flutings is to secure a distribution normal to the direction of the incident light. The external surface of the globe consists of a series of circular grooves in a horizontal plane extending over the entire surface of the globe. These grooves are constructed with reference to the relative positions of the groove and the source of light. The committee reported that when the light from an arc lamp passed through the globe, the effect upon a vertical screen showed a distinct cutting down of the amount of light passing in a straight line through the upper part of the globe, and a definite increase of the light on a horizontal plane and at all angles below that plane, the space vertically beneath the globe being well illuminated. The fact that the diffusion is secured is shown by the character of the shadows cast. When an opaque body is held near the globe there is practically no shadow on a screen a few feet away. This property of the globe has the effect of entirely doing away with distinct shadows of bodies near it that is so objectionable in the ordinary arc light. In appearance the holophane globe is covered with bright points over its entire surface. Recent tests by Professor Lewes, of London, with a Welsbach mantle and one of these globes showed that in the angle between the horizontal plane and forty-five degrees below it the holophane globe increased the light from twelve to thirteen per cent, while the best of a number of others examined, a clear glass globe, gave a loss of 7.5 per cent. The general conclusions by the committee regarding the globe were that "Messrs. Blondel and Psaroudaki have invented a globe that secures much better diffusion and more satisfactory distribution than any other globe known to its members; that the conditions of its manufacture are such that it can be supplied to the trade in commercial quantities; and that the invention has secured a distinct improvement in the diffusion and distribution of artificial light." The committee recommended that the John Scott Legacy medal and premium be awarded to the inventors.

 

Epicurean Cats and Dogs.—While most instances in which eccentricities of animal tastes have come under observation are those in which animals, like dogs and cats, are