ADVERTISEMENT. 



The object of the General Appendix to the Annual Eeport of the 

 Smithsonian Institution is to furnish brief accounts of scientific discov- 

 ery in particular directionsj occasional reports of the investigations 

 made by collaborators of the Institution ; memoirs of a general charac- 

 ter or on special topics, whether original and prepared expressly for the 

 purpose, or selected from foreign journals and proceedings; and briefly 

 to present (as fully as space will permit) such papers not published in 

 the Smithsonian Contributions or in the Miscellaneous Collections as 

 may be supposed to be of interest or value to the numerous correspond- 

 ents of the Institution. 



It has been a prominent object of the Board of Eegents of the Smith- 

 sonian Institution, from a very early date, to enrich the annual report 

 required of them by law, with memoirs illustrating the more remarka- 

 ble and important developments in physical and biological discovery, 

 as well as showing the general character of the operations of the Insti- 

 tution ; and this purpose has, during the greater part of its history, been 

 carried out largely by the publication of such papers as would possess 

 an interest to all attracted by scientific progress. 



In 1880 the Secretary, induced in part by the discontinuance of an 

 annual summary of progress which for thirty years previous had been 

 issued by well-known private publishing firms, had prepared by com- 

 petent collaborators a series of abstracts, showing concisely the promi- 

 nent features of recent scientific progress in astronomy, geology, meteor- 

 ology, physics, chemistry, mineralogy, botany, zoology, and anthropol- 

 ogy. This latter plan was continued, though not altogether satisfac- 

 factorily, 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 original) 

 embracing a considerable range of scientific investigation and discus- 

 sion. This method has been continued in the present report, for 1890. 



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