A large amount of original work is accomplished each year in these laboratories, both by students and professors. During the year 1897-98, for instance, four books and sixteen articles on chemical subjects came from them. In the development of sanitary chemistry the Institute has been particularly prominent. Beginning with the careful and thorough investigations made by Professor Nichols for the State Board of Health, the reputation of the institute in this direction has been still further increased by the recent extensive investigations of Professor Drown and Mrs. Ellen H. Richards, made for the same board in connection with the examination of the purity of the water supplies of the State, and the experiments at Lawrence relating to the best methods for purifying water and disposing of the sewage of inland towns. An illustration of the policy of the school in separating out a subject whenever it is found capable of complete theoretical and practical treatment and putting it into the hands of some assistant professor for development, is found in the laboratory for gas and oil analysis, which for some years has been in charge of Dr. Gill. In this laboratory, investigations are made relating to chimney gases, as well as questions of fuel, furnaces, gas firing, etc., while oils are tested and analyzed with reference to specific gravity, viscosity, friction, flashing and firing points, and liability to spontaneous combustion. The same policy is further illustrated in the establishment in 1894 of a well equipped laboratory devoted entirely to physical chemistry; that is to say, to the relations between chemical changes and heat, light and electricity. This laboratory, under the charge of Dr. H. M. Goodwin, occupies a room measuring 28 by 29½ feet, and is devoted to photographic work, experiments in electrical conductivity, thermo-chemistry, molecular weight determinations and experiments in chemical dynamics. More recently still, a complete option in electro-chemistry has been established, to meet a growing demand. [Illustration: PART OF THE ELECTRICAL ENGINEERING LABORATORY.]