Professor A. Lawrence Rotch h. '91, of the department of Geology, will give a stereopticon lecture on "The Route of the Air" in the Living Room of the Union this evening at 8.15 o'clock. The lecture will be open only to members of the Union.

In 1885 Professor Rotch established the Blue Hill Meterorological Observatory, of which he is now the director. This observatory is famous for its investigations of the clouds and it was there that kites were first used to record meteorological data. In recognition of his efforts to advance the knowledge of the atmosphere Professor Rotch was made a Chevalier of the Legion of Honor, and he has also received the Prussian Orders of the Crown, and of the Red Eagle.

Besides editing the "Observations and Investigations at Blue Hill", which are published regularly in the "Annals of the Harvard College Observatory", Professor Rotch has written two books on his work, "Sounding the Ocean of Air", and "The Conquest of the Air".