The 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. 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 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 Professor Wundt. In the days when the eye-and-ear method of observation prevailed, the astronomer had both to watch his 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 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 hundred young farmers were enrolled in the Agricultural Reading Course. Much interest seems to have been shown by farmers in sugar-beet culture, in investigations of which more than three hundred of them are cooperating with the station, and two hundred in experiments with fertilizers. NOTES.