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POPULAR SCIENCE MONTHLY.

of American Ethnology has been prosecuted in the study of social organizations, linguistics, and decoration, as illustrated in the Indian tribes. The International Exchange Service, instituted in 1852, is still carried on, with 28,008 correspondents on its records, of which 21,427 are foreign. The operations of the Astrophysical Observatory have consisted chiefly in experiments in the holographic analysis of the infra-red solar spectrum and the preparation of a report thereon. Information has been sought from the institution on all sorts of subjects, and has been furnished, or else the way to get it has been pointed out.

 

Dinner in the "Zoo."—The appetites of the twenty-five hundred animals, more or less, kept in the London Zoölogical Gardens furnish a curious field for study; and the matter of dealing with them is in some cases one of great difficulty. Only one animal—the hog—seems wholly indifferent as to the nature and quality of its food, and some species are extremely fastidious. Even the ostrich manifests a choice, and shows no relish for the nails and old iron with which it is credited with regaling itself on the African farms; and one species, the Somali ostrich, accepts only green food, refusing to touch the meat and biscuits of which the South African ostrich is very fond. The giraffe is one of the daintiest of beasts, living in nature on the leaves which it strips from trees, and in the gardens on the best clover hay, crushed oats, bran, and chaff, with fresh green tares and an occasional onion as relishes; and while it is very fond of fresh, whole apples, rejects one that has been bitten. Some animals are able to change their native tastes and acquire others, vegetarians becoming flesh eaters, and insect eaters turning to fruit and grain—as the kea, of New Zealand, which, once a strict vegetarian, has become very fond of mutton. Animals in the Zoo have to submit to more or less of this, for their native food is often unattainable. Nothing has been found on which the Australian koala will thrive, but the kangaroos and wallabies take kindly to grass and maize, and breed frequently. Unfortunately, the kangaroos are very subject to gout and corns. The polar bear is happy with horse blubber and plaice, and the crocodiles and alligators are satisfied with raw meat. The apteryx, which at home lives on worms and larvæ, feeds and prospers on imitations carved out of fillet steak.


MINOR PARAGRAPHS.

The debate concerning the presence or absence of considerable bodies of water on Mars has taken a new direction, and observers are now looking for optical evidence. If there is any large body of water on the planet, the image of the sun should be seen, when the proper conditions for the phenomenon exist, reflected from its surface as a fine point of light. No such image has been observed by the astronomers who have busied themselves most with Mars; and the conclusion is drawn that the planet's store of water is derived from the melting of the polar snows. Mr. Taylor, of York, believes that there is enough of this to affect the hue of the vegetation, the existence of which is indicated by dark lines and spots. There does not appear to be anything in this theory to preclude the possibility of Mars having a copious supply of rain.

While admitting that water may be an effective agent in making deposits like loess, M. J. A. Udden adduces reasons in the Bulletin of the Geological Society of America for believing that the loess in the Mississippi Valley was chiefly deposited from the air. It is often found in situations where the agency of water can hardly be predicated, and contains land shells. The universal presence of mineral dust in the atmosphere and its constant settling necessitate its accumulation in places where erosion is at a standstill or does not exceed the rate of atmospheric sedimentation; and the conditions now nearly correspond with this. In mechanical composition fine wind sediments and loess are largely identical. The loess beds are more uniform in structure than deposits from water can well be; and other features of the loess appear easier to explain if it be regarded as a land deposit.

The law of wills and inheritance is cited by Isaac F. Russell, in a paper on the Vendetta, as perhaps exhibiting more than any other