Page:Popular Science Monthly Volume 16.djvu/895

 the chief of the important town of Falaba, which defeated the attempts both of Laing and Reade to reach the sources. The crossing of the mountains appears, however, to have been a difficult undertaking, not accomplished without much determination, aided by good luck. The main source was found on the frontier of Kirsi and Koranka; in short, near the place indicated on Major Laing's map.

Animal Heat of Fish.—Surgeon J. H. Kidder, of the United States Navy, made some observations during last summer in connection with the United States Fish Commission at Provincetown, Massachusetts, to test the belief which is still held by many, even scientific observers, that fish are cold blooded—that is, that they take on the temperature of the water which surrounds them, with no power to resist it, and that they develop little or no animal heat themselves. Observations made in the usual way, by inserting the thermometer into the rectum of the fish, agreed with the generally received opinion, the fish showing in that part but little higher temperature than that of the surrounding water. It was judged, however, that neither the rectum, which is closely exposed to the water, nor the arterial blood, which has passed through the gills where it is exposed and cooled, could have the same value as representing the body-temperature in fishes that corresponding parts possess in mammals and birds, but that the degree of heat actually developed in the life-processes should be sought in the venous circulation and the branchial artery. The fish were accordingly opened as soon as possible after they were taken out of the water, and the bulb of the thermometer was inserted into the cavity of the heart, or the branchial artery. Most of the fishes showed a perceptibly higher temperature than that of the water, rising, in the case of the dogfish, to 12°. A young dogfish, taken from its mother's oviduct, was 20° warmer than the water. The number of observations was not large enough to warrant a final statement of the degree of animal heat presented by the several fishes, but they are held to prove that fish develop sufficient heat to warm again, to the extent of from 3° to 12°, blood that has been cooled in each circuit to the temperature of the surrounding water. An apparent exception to the general result was offered in the case of bluefish, which were cooler than the water; but that was supposed to be because they had come up from a greater depth and a colder stratum of water than that on the surface.

Sun-Spots and Rainfall.—Mr. E. D. Archibald writes in "Nature" that, instead of changes in the condition of the sun necessarily affecting every part of the earth in the same way, we have many meteorological analogies which favor the notion that totally opposite effects may arise in different parts of the earth from the action of the same primary causes. Thus, it is generally assumed that the same tropical heat which gives the primary impulse to the desiccating northeast trade-wind of subtropical latitudes, furnishes the energy which exhibits itself in the almost constant precipitation under the equator. Any variation in the degree of this heat should consequently affect places in the region of the trades and in the equatorial calm-belt, in a diametrically opposite manner. The great rainfalls of last autumn in England and India were ascribed by some to the sun's emergence from a period of years marked by the rarity of its spots, and shining with increased radiations on the southern oceans; but Mr. Archibald shows that the rainfall of England, between latitudes 50° and 55° north, reached a decided maximum in 1877, a year of extreme spot-minimum, and was very high all through the recent period of unusually marked spot-minimum. A table of the annual mean range of barometric pressure at Calcutta from 1840 to 1878, of which Mr. Archibald gives a summary in his communication, indicates that years of few sun-spots were characterized by higher temperatures, greater wind-velocity, and greater range of barometric pressure than those of many spots.

New Bleaching Preparation.—A method of applying the ordinary bleaching agents (hypochlorites) in a new way has been invented by Count Dienheim de Brochocki, of Paris. Instead of immersing the goods to be bleached in an ordinary "chloride-of-lime" vat, and subsequently scouring, the inventor