296 REVIEWS -CHEMICAL METHOD, KOTATION, «fec. 



many of our present theories aud assumptions an; but echoes of what 

 we once were taught to consider absurd. Chemistry is essentially 

 progressive, and a science of facts ; theories and views, founded on a 

 comparatively small number of facts, must necessarily receive altera- 

 tion when new facts, bearing on these theories, an; discovered. We 

 should scarcely be willing to adopt Williamson's explanation of the 

 nature of ether and of its forma Lion, were it not for the discovery of 

 the compound ethers: the discovery of the compound anhydrous acids 

 has Vd to some remarkable changes in our theories respecting the 

 organic acids generally. 



Liebigmore than once quizzed Laurent about his spirit of prophecy, 

 but was in himself a remarkable instance of a true propht, having 

 predicted in 1839 the existence and properties of the compound 

 ammonias, which were discovered in 1849 by Wurtz. 



The idea of the dualistic nature of the vegetable alkaloids, main- 

 tained by several of the older chemists, seems to be entirely refuted, 

 for we can scarcely believe that the composition of the natural pro- 

 ducts can be different from that of the artificial ones which they so 

 closely resemble. It is not at all extraordinary that those who 

 commenced the study of chemistry when that science was almost in 

 its infancy, and when all organic relations were compared to inorganic, 

 should have been induced to extend to the one department, the 

 dualistic theory so generally adopted in the other ; every man has his 

 own peculiar hobby, swear3 by his own side of the shield, and is very 

 unwilling to admit the arguments of others. For long years the 

 conflict raged among chemists of the different schools, but at the 

 present day there seems to be a fusion between the opposing factions, 

 while portions of the compound radical theory are conceded to be 

 erroneous, parts of the Laurentian hypotheses, and of those of the 

 newer French school, are willingly adopted. 



Laurent's papers are diffused through so large a numbnr of journals, 

 and his views have been so imperfectly represented in most manuals 

 of chemistry, that the publication of this excellent translation of his 

 last work (on which he was engaged, as Eiot says, even when in the 

 grasp of death.) will prov;.' an exceedingly acceptable addition to the 

 library of everj 



Laurent alludes to most of the attacks which have at different 

 times been made upon his theories and researches by Berzelius, Liebig, 

 Wohler and others, and with no feeble pen makes a fierce onslaught 

 upon the dualistic hypothesis. However ingenious his propositions 

 with regard to chemical nomenclature, we cannot conceive that they 

 will ever be generally adopted ; nitron aphthase and nitronaphthise are 



