980 ON THE DENSITIES OF OXYGEN AND HYDROGEN, AND ON THE RATIO OF THEIR ATOMIC WEIGHTS. BY EDWARD W. MORLEY, PH.D. CITY OF WASHINGTON: ADVERTISEMENT. The present memoir is the result of a series of investigations by Professor Morley, which have been aided to some extent during the last two years by the Smithsonian Institution. The atomic weight of oxygen may be called the base line upon which practically our entire system of atomic weights depends, and a small error in its measurement becomes large by multiplication in the higher parts of the atomic weight scale. Hence its accurate determination is of fundamental importance. In his investigation, Professor Morley has studied the problem by two methods. 1st. By the synthesis of water, in which he, for the first time, has achieved completeness by actually weighing the hydrogen, the oxygen, and the water formed, whereas all his predecessors took one or another of these factors by difference. 2d. By the density ratio between oxygen and hydrogen. In this method he has weighed the gases of greater purity and in larger quantity than hitherto, and he has in some instances operated without the intervention of stopcocks, and therefore with no possibility of error due to leakage. He has also, as a correction to the density ratio, redetermined the composition of water by volume. By both methods he reaches the same result: O 15.879, with variation in the fourth decimal place as between the two. 0 = In accordance with the rule adopted by the Smithsonian Institution, the work has been submitted for examinationu to a committee consisting of Professor F. W. Clarke and Doctor Carl Barus, and having been recommended for publication it is herewith presented in the series of Contributions to Knowledge. SMITHSONIAN INSTITUTION, Washington, July, 1895. S. P. LANGLEY, Secretary. |