Appendix VII. 



REPORT OF THE EDITOR FOR THE YEAR ENDING JUNE 30, 1897. 



.Sir: I have the liouor to submit the following report on the publicatioDs of the 

 Smithsonian Institution for the year ending June 30, 1897 : 



I. CONTRIBUTIONS TO KNOWLEDGE. 



Two memoirs of the Contributions have been issued this year, each of them hav- 

 ing been submitted in the Hodgkins fund prize competition. 



No. 1033. Argon; a New Constituent of the Atmosphere; by Lord Rayleigh and 

 Prof. William Ramsay. (Part of Vol. XXIX of Smithsonian Contributions to 

 Knowledge.) Quarto pamphlet of 43 pages, illustrated with 5 text figures. 



This memoir was submitted in competition for one of the Hodgkins Fund prizes 

 offered by the Smithsonian Institution, aud the first prize of $10,000, for a treatise 

 embodying some new and important discovery in regard to the nature or properties 

 of atmospheric air, was awarded to Lord Rayleigh aud Professor Ramsay for their 

 discovery of "Argon,' a new element of the atmosphere. The authors give a detailed 

 description of the apparatus and methods of their investigation. 



No. 1034. Atmospheric Actinometry and the Actinic Constitution of the Atmos- 

 phere; by E. Duclaux, professor of physics in the Agronomical Institute at Paris. 

 (Part of Vol. XXIX of Smithsonian Contributions to Knowledge.) Quarto pamphlet 

 of 48 pages. 



Professor Duclaux summarizes his work as follows : 



"1. The oxidation of oxalic acid in a weak solution takes place mainly, and almost 

 exclusively, under the influence of the chemical rays of solar light; it can therefore 

 be used as an actinometric measure. 



''2. It depends on the concentration of the liquid, which for the best results should 

 not exceed about 3 grams per liter. 



"3. With an equal volume of solution combustion decreases as depth increases. 

 There is an absorption of chemical rays, although the liquid is and remains very 

 transparent. 



"4. For equal depths of liquid, combustion is proportional to the surface, aud con- 

 sequently also to the volume. 



"5. It depends on the age of the solution — that is to say, of the time which has 

 elapsed since preparation. As it grows older an oxalic solution becomes more sensi- 

 tive and attains a certain maximum which is quite stable and quite regular. It is 

 well to wait till this state of sensitiveness has been produced. 



"6. The daily combustion, such as is measured with stej'ilized liquids, varies from 

 one day to another much more than any other meteorological phenomenon, and, while 

 subject to the influence of what we call ' fine weather' and 'overcast weather,' it 

 manifests very clearly other influences which are less visible. 



" 7. It shows also the influence of the seasons, and manifestly exhibits a maximum 

 in spring. 



"8. It is but feebly subject to the influence of altitude. 



"9. On the other hand, it betrays so strongly the presence of divers oxidizahle 

 essences or 8ul>stances in the air that we must consider local and daily variations 

 as due to the presence in the atmosphere of actinic clouds, which are discoverable 

 only by the reduction and absorption which they produce in the chemical radiations 

 of sunlight. 



"10. The atmosphere of extreme northern regions is less absorbent than that of 

 our temperate zones, and, consequently, at the same hours of the day actinic radia- 

 tion is more powerful, at the level of the soil, in the north than at the center of 

 Europe. 



71 



