The 93rd meeting of the American Association for the Advancement of Science, which will bring 3,000 scientific men to Boston and Cambridge, will be held in the Harvard and M.I.T. buildings during the Christmas recess. Harvard is playing host in a large measure to the Association and its affiliated organizations, which altogether make up a grand total of 20,000 persons interested in science in some form or other.

President Lowell and President Compton of M.I.T. will be the honorary chairman and honorary vice-chairman respectively of the local committee. Dr. Samuel C. Prescott, of M.I.T., will be the acting chairman, Kirtley F. Mather, Professor of Geology, the vice-chairman, Professor A.L. Townsend, of M.I.T., the secretary, while Henry L. Shattuck '01, treasurer of Harvard, will act as treasurer.

Memorial Hall is to be used during the meeting to display scientific apparatus, experiments, and the most recently discovered phenomena collected from all over the world. One piece of machinery, using a microscope camera, takes pictures of microbes whirling around on a disk at the rate of 20,000 revolutions per minute. It is used to study the effects of rough handling on marine animals.

In addition to the various technical sessions, there will be lectures of popular interest to the public. Outstanding among these will be an address by the honorable Henry A. Wallace, Secretary of Agriculture; on "What can the engineer do for agriculture?"