6i8 



THE POPULAR SCIENCE MONTHLY. 



To the Editor of the Popular Science Monthly. 



Reading an item, attributed to a writer 

 in Science Gossip, on the " Food of the 

 Water-Tortoise," in the " Popular Miscel- 

 lany" of your July number, showing that 

 that reptile appears " to have a special rel- 

 ish for the food of the cat," it occurred to 

 me that I might also relate a fact which 

 came under my own observation bearing 

 upon this subject : During last summer I 

 found an ordinary snapping-turtle {Chelydra 

 sei'pentina) in a field adjoining my residence, 

 and near a brook which empties into Boone 

 River, a few rods below. It was a vicious 

 old fellow, and more than ordinarily curious 

 to me from the fact that it had more than a 

 hundred leeches clinging to its shell and 

 various portions of its skin. I had some 

 suspicions that my captive had committed 

 depredations upon my young black Cayuga 

 ducks ; but dishking to murder it " in cold 

 blood," I let it go, and it speedily disap- 

 peared in a deep hole in the brook. Some 

 days afterward, while passing near the 

 place, I heard a duck squawling and splash- 

 ing in the water, and went at once to learn 

 the cause. I found that this same turtle 

 had seized one of my ducks by the foot, 

 and was trying to drag her under the water 

 tor " carnivorous purposes ! " The duck 

 was full-grown, and would have weighed 

 five or six pounds, but would soon have 

 been killed if I had not rescued it. I got 

 hold of the bird and drew her to the shore, 

 but the turtle held on, till I was able to 

 secure him. Of course, he caught no more 

 of my ducks. 



But this reminds me of another inter- 



esting fact. These black Cayuga ducks 

 said to have descended from ancestors capt- 

 ured at Cayuga Lake, New York, by reason 

 of long domestication and highfeeding have 

 come to have very heavy bodies and short, 

 small wings. Owing to the disuse of the 

 latter, they have become so far atrophied 

 that " well-bred " birds are quite incapable 

 of flight. In the summer of 1875, one of 

 my half-grown ducklings had the misfortune 

 to lose one of its legs. After some days' 

 absence it hobbled home from the river on 

 one foot, the other having no doubt been 

 torn off by one of these same predacious 

 turtles. The little bird speedily recovered 

 from the injury, though it never attained the 

 full size of its mates. It hopped about quite 

 briskly on its single foot, using its wings to 

 surmount obstacles or increase its speed. 

 The consequence was that its wings grew to 

 such size and length that it was capable of 

 flying twenty or thirty rods, and possibly 

 much farther. It could rise easily out of the 

 water, and once on the wing was able to 

 clear the bank and a high fence in all, a 

 quite abrupt rise of fifteen or twenty feet 

 and thus speedily reach home, while its 

 mates were slowly w^addling through the 

 grass. My flock of ducks showed in a striking 

 manner the result produced by the long dis- 

 use of their wings ; while the unfortunate 

 one-legged bird as strikingly evidenced how 

 rapidly " compulsion to more diligent use" 

 produced a very decided and important 

 modification of the wings, increasing their 

 strength, as well as the length of the feath- 

 ers. Charles Aldhich. 

 Webstee City, Iowa, July 6, 1877. 



EDITOR'S TABLE. 



SPECTROSCOPIC DISCO VER Y OF OXYGEN 

 IN THE SUN. 



CELESTIAL chemistry has taken 

 another stride forvrard. In a 

 paper recently read before the Ameri- 

 can Philosophical Society, and printed 

 in the American Journal of Science 

 and Arts, Dr. Henry Draper announces 

 the discovery of oxygen gas in the sun, 

 the fact being arrived at and verified 

 by a long course of spectroscopic ob- 

 servations. 



Viewed in any of its numerous as- 

 pects, this discovery is of immense in- 

 terest. Whether as an extension of our 

 knowledge of solar physics, solar chem- 



istry, and the nature of the spectrum 

 itself, or as throwing further light upon 

 the constitution of the universe ; wheth- 

 er as bearing upon cosmical theories 

 that have attracted much attention, or 

 as a triumph over the difficulties of com- 

 plicated experiment, or, finally, as an 

 illustration of hereditary genius in sci- 

 ence, where a line of research opened 

 brilliantly by the father nearly half a 

 century ago, has been pursued with 

 equal brilliancy to this crowning result 

 however regarded, this exploit of the 

 younger Draper must command un- 

 qualified admiration. 



As has been repeatedly shown in our 



