28 REPORT OF THE SECRETARY. 



computing these quantities for the old planets has already been per- 

 formed three or four times over — a labor which these tables would 

 have saved, and will save in the future for all the planets whose mean 

 distances are not at present sufficiently well known. The supplement 

 to the tables contains the qualities necessary in the computation of the 

 mutual perturbations of the eight principal planets ; and the supple- 

 ment continued, which will be published during the present year, will 

 contain the quantities which correspond to the asteroids. In order to 

 ensure accuracy in printing these tables, they have been stereotyped. 

 The work was referred to Prof. B. Peirce, of Harvard University, and 

 Capt. C. H. Davis, Superintendent of the American Nautical Almanac, 

 and it is published on their recommendation. 



Another paper which has been accepted for publication, and is 

 now ready for distribution, is by Prof. Wolcott Gibbs, of New York, 

 and Dr. F. A. Genth, of Philadelphia, entitled ''Eesearches on the 

 Ammonia-cobalt bases." It consists of a laborious series of investi- 

 gations relative to a very interesting part of chemistry . This memoir 

 is chiefly important from a theoretical point of view, though it will 

 probably be found to possess many important practical applications. 

 Chemists have long recognized the existence of a class of bodies called 

 bases, which possess the property of neutralizing acids, and of form- 

 ing with them what are commonly called salts. These bases are 

 usually oxides of metals, or of substances which play in combination 

 the part of metals. Thus the protoxide and sesquioxide of iron are 

 in this sense simple bases, while quinine, morphine, strychnine^ &c., 

 form examples of complex bases, or oxides of what chemists term 

 compound radicals. It usually happens that metals which belong to 

 the same natural family or group form oxides which have an analo- 

 gous constitution. Thus iron, manganes*, chromium_, cobalt, and 

 nickel all form sesquioxides as well as protoxides. The protoxides of 

 these metals are strong bases. The sesquioxides of chromium, iron, 

 and manganese are also bases, while those of cobalt and nickel rarely, 

 if ever, exhibit basic properties. Under these circumstances, it is very 

 interesting to find that the union of the sesquioxide of cobalt with a 

 few equivalents of ammonia, or of ammonia and deutoxide of nitrogen, 

 confers upon it the property of forming stable combinations with acids, 

 or, in other words, salts. In the memoir referred to, four distinct 

 classes of such compound bases are described. Of these, two are en- 

 tirely new, while the others had^ up to this time, been very imper- 

 fectly investigated. 



The bases described in the memoir are termed conjugate, from the 



