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268
THE POPULAR SCIENCE MONTHLY

trees cut down by beavers as opportunity offered, out of two hundred and seventeen measurements of trees, from two to eighteen inches thick, seventy-nine were cut equally on all sides; ninety-two were cut from one fourth to one half inch farther in on one side than the other, and forty-six considerably exceeded this difference. I do not know the cause of this variation, but suspect it comes from attempts to fell trees in certain directions.

Even the houses of the beavers are subject to occasional variation. When going through some of their dwellings in a beaver dam north of Grand Lake, Colorado, I was struck by one exception to the type-form described by Dr. Stockwell. It had two distinct stories, the lower being partly under water, and partly filled with twigs of quaking-asp. The upper story had the rough walls smoothed inside by having every crevice filled with dead leaves, the whole being almost as smooth as the interior of a bird's nest, I examined many other beaver-houses along the Grand and the tributaries of Grand Lake, but failed to find any that were as elegantly fashioned in the interior as this one.

The facts detailed that came under my observation have confirmed me in the heretical opinion that the older observers, who studied the beaver at close range, drew as little for their facts on their imaginations as the modern naturalists.

Samuel Aughey.
Lincoln, Nebraska.
 

 

CURIOUS CHANGE OF HABIT.

Messrs. Editors:

The following sketch of a change of habit in a species of snake, the Liopeltis vernalis, will doubtless prove interesting to some of the many readers of your valuable "Monthly":

A week or two ago, while walking in the garden, my attention was attracted by the curious actions of the cat, which seemed to be suffering from an epileptic fit, jumping, rolling, and scratching at a great rate. A closer approach revealed that he was busily engaged in trying to throw off a beautiful green snake (the Liopeltis vernalis), which in its efforts to escape the claws of its foe, had coiled itself around the cat's body, much to the latter's discomfort. There was no apparent effort at constriction made by the snake, who was evidently waiting for a good chance to escape. Finally, the snake uncoiled itself and tried to seek safety by flight. It was caught, however, while crossing a wide path between the bushes, and handled unmercifully. While struggling under a lilac-bush, about six feet high, a sudden thought, born of necessity, seemed to animate the snake. It twitched itself loose from the grasp of the cat, made for the slender trunk of the lilac-bush, or rather shrub, encircled it, and in a few seconds had made its way to the very top of the shrub, across which it lay extended, watching the futile endeavors of the cat to climb the slender stem of the shrub. After repeated failures, the cat lay down at the foot of the bush, like a tiger waiting for his prey. The resemblance was very striking, the cat being of a tawny gray color with dark bands, a perfect tiger en miniature. This blockade continued more than an hour, when the snake took advantage of the momentary inattention of the cat, and quietly glided on to the tops of the adjoining gooseberry-bushes, until he had put about ten feet between his foe and himself. He then glided to the ground, and made his escape, unmolested, much to the grief of my little girl, who wished to have the beautiful little reptile as a pet. The cat continued his blockade for some time longer. He could not be coaxed away until I took him up and held him among the top branches of the shrub, letting him see that the snake was gone.

While every snake has sufficient sense to take hold of anything on which it may be placed, it is very rare for the ordinary ground-snakes to so forsake or modify their terrestrial habit as to voluntarily seek protection above the ground, and thereby cultivating an arboreal habit. This same specimen, under similar circumstances, will, without doubt, pursue a similar course of action, and in time produce a race of terrestrio-arboreal Liopeltis vernalis, which, having an advantage over their less highly gifted brethren, according to the principle of the survival of the fittest, should become the final normal type of Liopeltis vernalis.

G. A. Brennan.
Roseland, Cook County, Illinois.
 

 

EXTENT OF THE RECENT EARTHQUAKE.

Messrs. Editors: Being interested in science, permit me to say that if you, or any one, proposes to collect facts relative to last Sunday's earthquake, I am quite sure it was felt here. During the afternoon I experienced a strange and unwonted quiver in the floor of my study and a slight movement of the window-sash. It drew my attention at the time as something different from what I had ever observed before. My room is so situated that no movements of persons about the house can shake the floor, and I am certain it was the earthquake. I neglected to note the time, or to suspect the probable cause, being very busy. But another member of my family noticed a strange movement in the house, and crackling sounds in the ceiling of another building were heard.