Columbia university. New York, is to have a mathematical museum, the nucleus of which will be I he collection of mathematical models purchased for the university by ex President Seth Low at the world's Columbian exposition in Chicago in 189?, and presented by him to the department of mathematics. Among other things will bo a collection of models constructed by Dr. Martin Schilling of italic, Germany, and also one belonging to Prof. Weiner of Darmstadt and a set of mathematical instruments from the institute of Dr. G. Coradi ofZurich.The new post office building In the City of Mexico is the first government bail ding in Mexico of any architectural design worthy of the name. It