440 Notices respecting^N'ew Books. 



js no longer correct, as his recent discovery of the extraop? 

 dii>ary detonating substance From the combination of chlo- 

 rine with ammonia, renders it probable that chlorine may 

 be combined with azote. Of the various acids denomi- 

 nated from nitre, Sir H. observes that according to the 

 principles of the French nomenclature, they should be 

 called hydro-r\\\r\c or lnjdro-x\\u-nv\9.. When the author 

 discovered a solid hydrat of phf)sphorous acid in Feb. 1812, 

 he also recognised the existence of an elastic fluid, pro- 

 duced with solid phosphoric aciil by heating the hydrat jn 

 a retort out of the contact of air. This product he calls 

 hydrophosphoric gas, which in specific gravity is twelve 

 times heavier than hydrogen. It con'.aius four proportions 

 of hydrogen, and one of phosphorus : water absorbs about 

 one-eighth its volume of it. Phos-phorettcd hydrogen pro- 

 bably contains this gas in many experiments. The basi? 

 of borax, which the Profes'^or originally concluded to be 

 metallic, and consequently denominated it boracium, he 

 now calls boron, a"; subsequent experiments have not de- 

 iTionstrated its mctalhc nature. Boron is an opake, dark 

 olive-coloured powder, infusible and not volatile at any 

 known temperature; when strongly heated in contact with 

 air it burns, and forms dry boracic acid. iT is a non-con- 

 ductor of electricity, and insoluble in water. Much still 

 remains to be discovered respecting the operations of this 

 substance and its application to the arts, owing perhaps to 

 its hitherto comparative scarcity. Of the mctaU, Sir H. 

 has augn^enled their number to 39, five times the number 

 known to our ancestors. The sixth division, on substances 

 the nature of which is nfit vet certainly known, treats of 

 the fluoric principle, and the amalgam procured from am- 

 moniacal compounds. 



The seventh and last division of this part embracefi 

 a view of the analogies between undecompounded sub- 

 stances, ideas respecting their nature, the modes of se- 

 parating them, and the relations of theii^ compounds. Here 

 the autlior's almost universal knowledge of physical or, 

 chemical bodies enables him to trace the most curious and 

 interesting analogies in the apjjearances and operations of 

 matter, and the laws of the material world. The chain 

 of gradations in the metals, inflammable and other bodies, 

 leads to the conclusion that, as far as our knowledge ofth^ 

 nature of compound bodies has extended, " analogy of pro- 

 perties is connected with analogy of composition. We 

 know nothing of the true elements belonging to nature : 



but 



