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 considera- 

 bly 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 sub- 

 ject 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 dis- 

 tinct stories, the lower being partly under 

 water, and partly filled with twigs of quak- 

 ing-asp. The upper story had the rough walls 

 smoothed inside by having every crevice 

 filled with dead leaves, the whole being al- 

 most 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 he- 

 retical 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 Aughet. 

 Lincoln, Nebeaska. 



CURIOUS CHANGE OF HABIT. 

 Messrs. Editors: 



The following sketch of a change of 

 habit in a species of snake, the lAopeltis 

 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, jump- 

 ing, 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 constric- 

 tion made by the snake, who was evidently 

 waiting for a good chance to escape. Final- 

 ly, the snake uncoiled itself and tried to 

 seek safety by flight. It was caught, how- 

 ever, 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 advan- 

 tage 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 him- 

 self. 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 pro- 

 tection above the ground, and thereby cul- 

 tivating an arboreal habit. This same speci- 

 men, under similar circumstances, will, with- 

 out 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. 

 EosELAND, Cook County, Ili-inois. 



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 earth- 

 quake, I am quite sure it was felt here. 

 During the afternoon I experienced a stranpe 

 and unwonted quiver in the floor of my 

 study and a slight movement of the win- 

 dow-sash. It drew my attention at the time 

 as something different from what I had 

 ever observed before. My room is so situ- 

 ated 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 mem- 

 ber of my family noticed a strange move- 

 ment in the house, and crackling sounds in 

 the ceiling of another building were heard. 



