396 British Association for the Advancement of Science, 



6th, G. brevi-caudatus ,• 7 th, G. Otaria ; 8th, G. Burt oni. The author 

 enters into detailed descriptions of each of these species from original 

 specimens. M. Cuvier lastly considers the affinities of the Gerbillas 

 and Allactagas to the Gerboas, and concludes that the Gerbillas have 

 a much nearer affinity to the Muridce. 



BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE : 

 MEETING AT LIVERPOOL. 



Sept. 13. — Professor Graham made a communication on the sub- 

 ject of the Inorganic Salts, and in particular, on the function which 

 water discharges as an element of their composition. He had been 

 requested, at the meeting of the Association held in Dublin, to re- 

 port at some future meeting on the present state of our knowledge 

 of saline bodies; and his communication to the Section was under- 

 stood to have been made with the view of discharging the duty 

 which had been thus imposed on him. 



The Professor developed at some length his own views respect- 

 ing the constitution of salts. The hydrated acids are unquestion- 

 ably salts, having water as base, and they correspond in a remark- 

 able manner with the salts having for base magnesia, oxide of zinc, 

 oxide of copper, or any other oxide isomorphous with magnesia. 

 Hence water as a base belongs to the magnesian class of oxides. 

 Super or acid salts have two bases, of which water is one. They are 

 double salts, and correspond with the double salts of the same acids 

 containing magnesia, oxide of copper, &c. Thus the salt called the 

 binoxalate of potash is really a double oxalate of water and potash, 

 and corresponds in constitution with the double oxalate of copper 

 and potash, as will be seen on comparing their formulae below : 



K CC H CC H 2 , and 



K CC Cu CC H*. 



Mr. Graham's researches tend to prove that all salts are neutral 

 in composition, with the exception of certain specified classes. One 

 of these classes is the phosphates, of which there are three kinds, 

 containing respectively one, two, and three atoms of base to one 

 atom of acid, and for which the names of monobasic, bibasic, and 

 tribasic phosphates are proposed, in substitution for the old names 

 of metaphosphates, pyrophosphates, and common phosphates. In 

 some of the tribasic phosphates, the three atoms of base are all dif- 

 ferent, as in microcosmic salt, in which we have an atom of soda, 

 of ammonia, and of water, all united together, to one atom of phos- 

 phoric acid. Only one class of arseniates exists, but it is the tribasic 

 class ; it is likewise probable that the phosphites are all tribasic ; but 

 all the other classes of salts at present known, such as the sulphates, 

 nitrates, &c, are monobasic. In the case of those combinations 

 which are at present called subsalts, Mr. Graham finds that there 

 is really only one atom of base to one atom of acid. In the ordi- 

 nary neutral salts, such as nitrate of copper, we have several atoms 

 of water in combination with the salt, and known as water of cry- 



