ADVERTISEMENT 
The object of the Grnrrat Appenprx to the Annual Report of the 
Smithsonian Institution is to furnish brief accounts of scientific dis- 
covery in particular directions; reports of investigations made by 
collaborators of the Institution; and memoirs of a general character 
or on special topics that are of interest or value to the numerous 
correspondents of the Institution. 
It has been a prominent object of the Board of Regents of the 
Smithsonian Institution from a very early date to enrich the annual 
report required of them by law with memoirs illustrating the more 
vemarkable and important developments in physical and biological 
discovery, as well as showing the general character of the operations 
of the Institution; and, during the greater part of its history, this 
purpose has been carried out largely by the publication of such 
papers as would possess an interest to all attracted by scientific 
progress. 
In 1880, induced in part by the discontinuance of an annual sum- 
mary of progress which for 30 years previously had been issued by 
well-known private publishing firms, the secretary had a series of 
abstracts prepared by competent collaborators, showing concisely the 
prominent features of recent scientific progress in astronomy, geol- 
ogy, meteorology, physics, chemistry, mineralogy, botany, zoology, 
and anthropology. This latter plan was continued, though not alto- 
gether satisfactorily, down to and including the year 1888. 
In the report for 1889 a return was made to the earlier method of 
presenting a miscellaneous selection of papers (some of them origi- 
nal) embracing a considerable range of scientific investigation and 
discussion. This method has been continued in the present report 
for 1926. 
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