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Page:Popular Science Monthly Volume 44.djvu/730

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THE POPULAR SCIENCE MONTHLY.

began a study of natural history by the collection of eggs. Mr. Milne Redhead did not think the act of bird-nesting the greatest evil, but the collection of eggs for sale in large towns. Prof. Newton spoke of the practical impossibility of convicting bird-nesters on account of the difficulty of distinguishing between the eggs of one species and those of another.

 

Various Speeds.—The horse, said Mr. Jeremiah Head, in a paper recently read, though he could not walk faster than man, nor exceed him in jumping heights or distances, could certainly beat him altogether when galloping or trotting. A mile had been galloped in one hundred and three seconds, equal to thirty-five miles per hour, and had been trotted in one hundred and twenty-four seconds, equal to twenty-nine miles per hour. How man's position as a competitor with other animals in speed was affected by his use of mechanical aids, but without any extraneous motive power, was considered in reference to locomotion on land, in water, and in air. But the most wonderful increase in the locomotive power of man on land was obtained by the use of the modern cycle. One mile had been cycled at the rate of 27·1 miles per hour, fifty at twenty, one hundred at 16·6, three hundred and eighty-eight at 12·5, and nine hundred at 12·43 miles per hour. Unaided by mechanism man had shown himself able to swim for short distances at the rate of three, and long distances (twenty-two miles) at the rate of one mile per hour. He had also given instances of being able to remain under water for four and a half minutes. Credible eyewitnesses stated that porpoises easily overtook and kept pace with a steamer going twelve and a half knots, or, say, over fourteen miles an hour, for an indefinite length of time. This was five and fifteen times the maximum swimming speed of a man for short and long distances respectively.

 

Tendencies of Population.—In a paper read in the British Association, Mr. E. Cannan, of Oxford, sought to show that, contrary to the general belief that the population of the great towns is being increased almost as much by immigration as by excess of births over deaths, the excess of immigrants over emigrants, or net immigration, is rapidly diminishing, and seems likely to disappear before the end of the century. The net immigration into London in the last ten years was only fifty-six per cent of what it was in the previous ten years, and only sixty-three per cent of what it was thirty years before, when the population was two and a half millions less than it is now. In this matter London is by no means in advance of the other great towns. In Liverpool the net immigration was 68,000 in 1851 to 1860, 56,000 in 1861 to 1870, 49,000 in 1871 to 1880, but in 1881 to 1890 the balance was the other way, and there was a net emigration of 15,000. In the case of Manchester the decline of the net immigration was neither so continuous nor so great as in Liverpool, but it was considerable. In each of the first two decades it was about 32,000, then it rose to nearly 50,000, but in the last decade it has declined to 17,700. The three great Yorkshire towns, Leeds, Sheffield, and Bradford, showed considerable fluctuations. Into the three taken together the net immigration was 25,000 in 1851 to 1860; in 1861 to 1870 it made an enormous jump up to 78,000, and then dropped right down to 18,000 in 1881 to 1890. The net immigration into the towns was affected by migration between the towns and other countries as well as by migration between the towns and the rest of England and Wales.

 

Animal and Artificial Mechanism.—Comparing animal mechanism with artificial, Mr. Jeremiah Head said, in his sectional address at the British Association, that all animals were in their bodily frames, and in the intricate processes and functions which went on continuously therein, mechanisms of so elaborate a kind that we could only look and wonder and strive to imitate them a little here and there. The mechanical nomenclature of all languages was largely derived from the bodies of men and other animals. Many of our principal mechanical devices had preexisted in them. Mr. Head proceeded to consider how far man was in his natural condition, and had become by the aid of mechanical science, able to compete successfully with other and specially endowed animals, each in his own sphere of action. The bodily frame of man was adapted for life and movement