6 REPORT OF THE SECRETARY. 



I could spare from engrossing administrative duties to the prosecution 

 of two independent investigations which had engaged my attention for 

 several years before I became connected with the Institution, and which 

 I believe are likely to lead to important scientific and utilitarian results. 

 The first of these researches, that upon the solar spectrum, has been 

 carried on in the Astro-physical Observatory, and to it I have referred 

 more at length in the account of the observatory. The second 

 research, an investigation of certain physical data of aerodynamics, 

 has been continued with results which appear to be approaching the 

 time of publication. 



Prof. E. W. Morley's investigations on the density of oxygen and 

 hydrogen, referred to in previous reports as aided iu part by the Insti- 

 tution, have been completed, and his memoir is now in press. The 

 atomic weight of oxygen may be called the base upon which practically 

 our entire system of atomic weights rests, 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 funda- 

 mental importance. In his investigation Professor Morley has studied 

 the problem by two methods: 



(1) 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. 



(2) By the density ratios between oxygen and hydrogen. In this 

 method he has weighed the gases of greater purity and in larger quan- 

 tity 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, redeter- 

 mined the composition of water by volume. 



By both methods he reaches the same result: 0=15.879, with vari- 

 ation in the fourth decimal place as between the two. 



The valuable balance purchased for these investigations has been 

 returned to the Institution. 



The subscription has been continued for 20 copies of the Astronom- 

 ical Journal as a slight aid to its publication, the separate numbers of 

 the journal being sent regularly to foreign libraries and observatories 

 as exchanges of the Institution. 



A small grant was made to Dr. Carl Barus to enable him to continue 

 certain investigations. 



The researches that I have here referred to are connected altogether 

 with the physical sciences. In the biological sciences I may refer to the 

 work of the occupants of the Smithsonian table at Naples, though the 

 Institution's work in this field has been largely indirectly provided 

 through its connection with the National Museum. Investigations aided 

 by the Hodgkinsfund are mentioned elsewhere. 



