yield, quality of product and cost of production. Several trpes of byproducts are made from the potash recovered and the cost data on production of these are also determined. Pigment Manufacture. Small quantity pigment manufacture is carried out on green, blue and yellow chrome pigments. Separate and simultaneous precipitations of pigments are made and the efiects of time, temperature, concentration and rate of precipitation are studied. The pigments thus made are ground in linseed oil in a Kent paint mill and tested out on service panels. Cost data of production are also emphasized in this project. Electrolysis of Salt. Electrolysis of brine is conducted in a large cell erected by the members of the class and the effects of the temperature, concentration, and rate of flow of brine, together with crystallization and evaporation data on production of caustic soda axe closely observed. Arsenical Insecticides. This project has a decided local appeal. Calcium arsenate is prepared under different conditions of temperature, concentration, rate of precipitation, and raw materials. The cost of production of the different products is determined for comparison. Organic Chemicals. Several organic chemicals have been prepared because of specific interests certain students have had in them. Standard preparation formulae are used as a basis for study, the conditions assigned to the students consisting of variations on these formulae. The project enables students to determine the effect of changing conditions on the quality and yield of the chemical Hnd to determine the costs of production. It is hoped that other and more inteesting projects may be added in the future and that additional outside plants can be added to the list for cooperative work with the ;lass in industrial chemistry. Lack of suitable equipment for some of the studies has handicapped the work to some extent but progress is being made each year in building up the course.
Light-Bearing Ether Compressible, Says Physicist. The ether which is believed to pervade space and carry light may be compressible, according to the ideas of Dr. Ludwik Silberstein, of the Eastman Kodak Company's research laboratory. I n a recent statement to Science Seruice, Prof. Albert Einstein, of relativity fame, differed with Dr. Silberstein's views, saying that the Stokes theory of the ether, on which Dr. Silbersteh's is based, would not explain the astronomical aberrations. I t was, he said, based on a mistaken idea that the velocity of the ether movement was deducible from a potential. "Against Prof. Einstein's contention," says Dr. Silberstein, "a velocity potential of the ether motion as required for the Stokes theory of aberration becomes possible a t once if the ether is assumed t o be compr?ssible. This was originally suggested by Planck, and was adopted by H. A. Lorentz, who hased on it a perfectly satisfactory theory of aberration. Allother phenomena then known were alsocovered by this theory. Whether the new experimental findings by Prof. Miller will necessitate a further modification remains to be seen."-Srience Semicc
