Page:Popular Science Monthly Volume 54.djvu/593

Rh H. F. Moore, of the Fish Commission, found only two kinds of food—copepods or "red seed," which appeared to constitute the sole food of the small herrings, and shrimps the principal food of the larger ones. In many cases the stomachs of the fish were densely gorged with these shrimps, which are extremely abundant in the waters of the vicinity. Excepting the eyes and phosphorescent spots beneath, which are bright red, the bodies of the crustaceans are almost transparent, yet such is the density of the schools in which they congregate that a distinctly reddish tinge is often imparted to the water. They are very active, and frequently avoid the rush of the fish by vigorous strokes of their powerful caudal paddles, which throw them several inches above the surface. To capture them requires some address on the part of the herring, and the fish likewise frequently throw themselves almost clear of the surface. When feeding upon copepods the movements of the herrings are less impetuous. They swim open-mouthed, often with their snouts at the surface, crossing and recrossing on their tracks, and evidently straining out the minute crustaceans by means of their branchial sieves. After they have passed the stage known as "brit," the herrings appear to feed principally at night, or if they do so to any considerable extent during bright daylight it is at such a depth that they escape observation. At night it is often possible to note the movements of the fish at a depth of several fathoms, and at such times Mr. Moore has seen them swimming back and forth, "apparently screening the water, their every movement traced by a phosphorescent gleam, evoked perhaps from the very organisms which they were consuming." The herrings evidently follow their prey by night, and the fact that the shrimps possess phosphorescent spots may explain the apparent ability of the fish to catch them then.



phosphorescence, which is so beautiful a characteristic of certain forms of animal life in the sea, has been the cause of much speculation among the fishermen and scientists; none of the proposed theories have been entirely satisfactory. It is now stated, however, that an adequate and provable cause has been discovered in a so-called species of photo-bacteria; by means of this germ it is stated that sea water, containing nutrient media, can be inoculated and rendered phosphorescent; that newly caught herrings with the sea water still fresh can be rendered phosphorescent by a treatment which favors the growth of the photo-bacteria. Oxygen is an essential to their growth.

equation was defined by Prof. T. H. Safford, in a paper read at the American Association, as in reality the time it takes to think; and as that time is different in different persons, observations are liable to be affected by it unless correct allowance is made for it in the case of each one. It has been a subject of discussion since the end of the last century. The Astronomer Royal of England discharged a good assistant in 1795, because he was liable to observe stars more than half a second too late. Bond, several years afterward, took the subject up and found that astronomers were liable to vary a little in their observations; some to anticipate the time by a trifle, and others falling a little behind. The subject has since been studied by Prof essor Wundt. In the days when the eye-and ear method of observation prevailed, the astronomer had both to watch bis object and to keep note of the time; with the introduction of the chronograph, the errors resulting from this necessity are in part obviated. But error enough still exists to be troublesome.

Educational Extension Work in Agriculture of Cornell University Experiment Station is carried on by the publication and distribution of leaflets, visitation of teachers' institutes, and other means that may bring the station in contact with the people. The results of the work have been generally satisfactory. Eight leaflets, on such subjects as How a Squash Plant gets out of the Seed, A Children's Garden, etc., were published last year in from two to six editions, and still meet a lively demand. Thirty thousand teachers were enrolled on the lists as receiving leaflets, or as students of methods of presenting Nature study to their pupils, sixteen thousand school children were receiving leaflets suitable to them, and twenty-five 