58 Analyses of Books. [July, 



subcarbonates. It decomposes soap wben assisted by heat ; as it 

 does also the alkaline sulphu: tets and hydrosulphuiets. No acid 

 acts upon it except those which occasion its decomposition. It 

 dissolves in hot solutions of potash and soda, and likewise in 

 ammonia, but less readily. The urates may be formed either by 

 mutually saturating the two constituents, or we may dissolve the 

 acid in an excess of base, and then precipitate by carbonate of 

 ammonia. 



The urates are all tasteless, and resemble in appearance uric 

 acid itself. They are not altered by exposure to the atmosphere. 

 They are very sparingly soluble in water. They are decomposed 

 by a red heat, which destroys the acid. The uric acid is preci- 

 pitated from these suits by all the acids except the prussic and 

 carbonic. They are decomposed by tite muriates, nitrates, and 

 acetates of barytts, str< ntian, lime, magnesia, and alumina. 

 They are precipitated by all the metallic solutions except that of 

 gold. 



When uric acid is exposed to heat the products are carbureted 

 hydrogen and carbonic acid, prussic acid, carbonate of ammonia, 

 a sublimate consisting of ammonia combined with a peculiar 

 acid. 



14* A Demonstration of Law son's Geometrical Theorems, by 

 the late Rev. Charles Wildbore; communicated by Mr. Mabbott 

 to Mr. Ewart, and by him to the Society.] This is a very curious 

 paper, and well worth the attention of the admirers of the 

 ancient method of geometry. But it is not susceptible of 

 abridgment, nor could we make it intelligible without trans- 

 cribing the whole paper ; we must therefore satisfy ourselves with 

 referring our mathematical readers to the essay itself ; and we 

 can promise them both amusement and instruction. Some of 

 the figures are so complicated as to make it somewhat trouble- 

 some to consult them. This results from the method of the 

 author, who has contrived to deduce the properties from each 

 other in a very beautiful manner. 



] 5. Remarks on the Summer Birds of Passage, and on 

 Migration in general. By Mr. John Gough.] In this ingenious 

 essay Mr. Gough shows that the opinion entertained by some 

 that the swallow, and other migrating bi ids, pass the winter in 

 a torpid state, is inconsistent with itself, and cannot be sup- 

 ported. The migrating birds feed on insects, and are compelled 

 to change their quarters when their food disappears. He shows 

 by direct evidence that the migrations of these birds, both to 

 the north and the south, take place not at once, but slowly and 

 gradually, according as the season advances, and gives facts that 

 show that in some cases a week elapsed before the chimney- 

 swallow moved a distance of six miles. lie terminates his essay 



