THE SMITHSONIAN INSTITUTION. 201 



applicable to his system of stereotyping catalogues of libraries, by 

 separate titles ; and in this way it will certainly be of great value, even 

 shonld it fail in other respects to reahze the sanguine expectations of 

 its inventor. 



Tlie result of the experiments will be submitted to a commission of 

 persons properly qualilied to judge of ils merits; and if their report be 

 favorable, a small sum will be allowed for the use of it. 



Besides the experiments mentioned under the head of meteorology, 

 made by Mr. Espy, on the cold produced by the rarefaction of air, Dr. 

 Hare, of Philadelphia, is employing articles of apparatus belonging 

 to the Institution, in a series of researches on the phenomena exhibited 

 in the air and in a vacuum by rubbing silicious minerals against each 

 other. The results of these experiments, with the drawings of the 

 apparatus employed, he intends to present to the Institution in the 

 form of a memoir for the Smithsonian Contributions to Knowledge. 



Comjmtatiojis. 



Occultations for 1851. — For the purpose of facilitating the accurate 

 determination of geographical points in the United States, a list of oc- 

 cultations and the co-ordinates of reductions for the 3'ears 1848, 1849, 

 and 1850, was prepared and pubhshed at the expense of the Smithso- 

 nian Institution. Congress has since ordered the publication of an 

 American Nautical Almanac ; and as lists of occulations will form a 

 part of this ephemeris, Mr. Preston, late Secretary of the Navy, directed 

 that the expense of computing these tables for 1850 should be defrayed 

 from the appropriation for the Almanac, provided the printing and 

 distribution were at the expense of the Smithsonian Institution. The 

 same course has been authorized by Mr. Graham, the present Secre- 

 tary of the Navy. 



Copies of these tables, computed by John Downes, of Philadelphia, 

 have been sent to all persons known to the Institution, who would pro- 

 bably make use of them in the way of improving our knowledge of the 

 geography of this country. They have been furnished particularly to 

 officers of the United States army, and other persons engaged in 

 exploring our new possessions and determining their boundaries. All 

 persons, to whom these tables were presented, have been requested to 

 send the result of their observations, made in connexion with the use 

 of them, to this Institution, or to publish them in some accessible 

 journal. 



Ephemeris of Neptune. — It was stated, in the last Report, that the orbit 

 of the planet Neptune, established by the researches of Mr. Walker, 

 and comprised in his memoir published by the Institution, gives the 

 data for calculating an ephemeris or tables of the daily position of this 

 planet, rivalling in precision the tables for any of the older planets. 

 Sets of these tables were computed and published for 1848 and 1849, 

 at the expense of the Smithsonian Institution ; but those tor 1850 and 

 1851 have been computed under the direction of Lieutenant Davis, 

 superiutendent of the Nautical Almanac, and at the expense of the ap- 

 propriation under his charge, while the expense of printing the tables 

 has been borne by this Institution. 



