measurement of base lines with the steel tape. After devising an apparatus for holding and supporting the tape, and measuring the coefficient of expansion of actual tapes, an application was recently made of the thermophone for determining the exact average temperature of the tape. This instrument, which was invented a few years ago by two Institute graduates, allows the average temperature of the tape to be measured within half a degree.
An interestingof the Institute, and one that has of recent years assumed great practical importance, is that of biology. It was organized in 1882, as an outgrowth of what was prior to that date the course in natural history, and now has a teaching force of six, under the direction of Prof. William T. Sedgwick, and occupies, with its laboratories and lecture-rooms, one entire floor of the Pierce Building. There are five distinct laboratories, fully equipped, with private rooms, store and preparation rooms, and a library and reading-room, and it is perhaps safe to say that nowhere in the United States is there so compact or well arranged a series of laboratories devoted chiefly to the sanitary, hygienic and industrial aspects of biology. The great advances in sanitary science in recent years have made bacteriology one of the most important, as well as one of the most practical, of the biological sciences, and the biologist has taken his place beside the chemist and the engineer in the study of the science and art of public sanitation. But bacteriology is of importance, not only in sanitary science, but also in its industrial relations. Great industries, like those connected with food preserving, canning, vinegar making, tanning and brewing, depend upon the activity or the exclusion of micro-organisms. As might be expected in a school of applied science, the development of the biological department in the Institute has been mainly along sanitary and industrial lines, rather than in the direction of zoölogy. The biological work in connection with the recent important investigations of the State Board of Health regarding the purification of water and the disposal of sewage, was done at the Institute, and early led to special instruction in these directions. In 1891 a course was established in the micro-organisms of fermentation, not only new to the Institute, but, it is believed, to the United States. Important researches had been made in Denmark in these lines, and in order to become thoroughly familiar with them, one of the instructors of the department spent a summer in the laboratory of Alfred Jorgensen, in Copenhagen. In 1896, a more elaborate course, that in industrial biology, was established, and since that time special studies have been made in various lines, such as the efficiency of sterilizing processes, the preparation of canned goods and the cultivation of butter bacteria. This department is destined to still greater development in the near future, and its laboratories are finely equipped in every direction.