FRAGMENTS OF SCIENCE. 



575 



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 ex- 

 tremely abundant in the waters of the vicin- 

 ity. Excepting the eyes and phosphores- 

 cent spots beneath, which are bright red, the 

 bodies of the crustaceans are almost trans- 

 parent, 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 fre- 

 quently throw themselves almost clear of the 

 surface. When feeding upon copepods the 



movements of the herrings are less impetu- 

 ous. They swim open-mouthed, often with 

 their snouts at the surface, crossing and re- 

 crossing on their tracks, and evidently strain- 

 ing out the minute crustaceans by means of 

 their branchial sieves. After they have passed 

 the stage known as " brit," the herrings ap- 

 pear 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. 



MINOR PARAGRAPHS. 



The phosphorescence, which is so beauti- 

 ful a characteristic of certain forms of ani- 

 mal 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 prova- 

 ble 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 ren- 

 dered 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-bac- 

 teria. Oxygen is an essential to their growth. 



Personal 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 differ- 

 ent persons, observations are liable to be af- 

 fected 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 antici- 

 pate 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 pre- 

 vailed, 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. 



The Educational Extension Work in Agri- 

 culture of Cornell University Experiment Sta- 

 tion is carried on by the publication and dis- 

 tribution 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 satis- 

 factory. 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 teach- 

 ers were enrolled on the lists as receiving 

 leaflets, or as students of methods of pre- 

 senting Nature study to their pupils, sixteen 

 thousand school children were receiving leaf- 

 lets suitable to them, and twenty-five hun- 



