REPORT OF THE SECRETARY, 11 



The memoir by Prof. E. Duclaux, of Paris, entitled Atmosplieric 

 Actinometry and the Actinic Constitution of the Atmosphere, describes 

 the methods and results of numerous experiments on the chemical 

 rays of the sun by the exposure of oxalic acid to their action. Pro- 

 fessor Duclaux found that the chemical action of the rays when the 

 sky was overcast was much less than on a fine day and that with light 

 cumulus clouds the combustion might be more active than with a clear 

 blue sky or slight cirrus, so that it appeared evident that the chemical 

 activity and hygienic power of the sun's rays are not rela.ted to the 

 apparent fineness of the day. 



Miscellaneous Collections. — Nine papers of the "Miscellaneous" series 

 were issued and others are in progress. The completed works were 

 Smithsonian Physical Tables, by Prof. Thomas Gray; Equipment and 

 Work of an Aerophysical Observatory, by Alexander McAdie; Air in 

 Eelation to Human Life and Health, by Prof. F. A. E. Eusseli; Air of 

 Towns, by Dr. J. B. Cohen; Air and Life, by Dr. Henri de Varigny; 

 Mountain Observatories, by Prof. E. S. Holden; Methods of Determin- 

 ing Organic Matter in Air, by Dr. D. H. Bergey; Eecalculation of 

 Atomic Weights, by Prof. F. W. Clarke, and Virginia Cartography, by 

 P. Lee Phillips. 



The Catalogue of Scientific and Technical Periodicals, by Dr. H. Car- 

 riugtou Bolton, mentioned in my last report, is in type and will soon 

 be published. It comprises the titles of more than 8,500 scientific and 

 technical periodicals in all languages, adding 3,500 titles to the first 

 edition published in 1885. 



There is also completed, ready for the printer, a voluminous supple- 

 ment to Dr. Bolton's Select Bibliography of Chemistry. 



As a special work, there has been printed the International Exchange 

 List of the Smithsonian Institution, being a list of the foreign corre- 

 spondents, aggregating 9,414 learned societies, museums, universities, 

 etc., with which American publications are exchanged. 



Annual reports. — The Smithsonian Annual Eeport is in two volumes, 

 one of which is devoted to the work of the National Museum. In the 

 general appendix of Part I are included memoirs on all branches of 

 knowledge, selected chiefly from publications of learned societies of the 

 world that are not readily accessible to the public, the basis of selec- 

 tion being that the papers are written by a competent person, give an 

 account of some important or at least interesting scientific discovery, 

 are untechnical in language and suitable to nonprofessional readers. 



The History of the First Half Century of the Smithsonian Institu- 

 tion, outlined with some detail in my last report, is now printed and 

 will soon be issued. The Institution was founded August 10, 1846, by 

 act of Congress approved by President Polk, and it seemed an appro- 

 priate memorial of the completion of its first fifty years to publish a 

 volume which should give an account of its origin and history, its 

 achievements, and its present condition. 



