ON account of the enthusiastic response to the Spectroscopy Conference held at the Massachusetts Institute of Technology last summer, which was attended by more than a hundred workers from America and abroad, it has been decided by the Institute to hold a second conference this year. A programme of papers and discussions is being prepared on the following topics, among others: absorption spectrophotometry (application to analysis of organic and inorganic substances and to the diagnosis and treatment of disease); analysis by the emission spectrum (determination of metallic and other atomic and molecular constituents of samples); biological and chemical effects of spectral radiation; spectro-scopy of the ultra-violet and infra-red; analysis of spectra, and measurement of wave-length. It is anticipated that the earlier sessions of the week will be of especial interest to biologists, medical research workers, and chemists. The main emphasis will then shift to subjects of chief interest to the industrialist and engineer, the geologist, and the metallurgist. The latter part of the week will be devoted to more theoretical problems of the spectroscopist. The meetings will be open to anyone interested in the topics under discussion. The Massachusetts Institute also announces a special programme of summer courses on spectroscopy and its applications to be given during the six weeks preceding the conference, which will deal primarily with applications of spectroscopy to biology, chemistry, geology, metallurgy, and mineralogy. Inquiries regarding the Conference and courses should be t addressed to Prof. G. II. Harrison, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts.