REVIEWS — CHEMICAL METHOU, KOTATIOK, &C. 297 



by no means preferable to nitro, biuitro, and trinitro-naphthalide, for 

 when we once assume that the numerical prefix shall indicate the 

 number of equivalents of hydrogen, replaced by N O 4 the words 

 nitro, binitro, and tririitro, indicate three numbers much more directly 

 and distinctly than the a, e and i in the final syllable of the Laurentian 

 names. In the present work we meet with an overwhelming mass of 

 new names with which it is sincerely to be hoped chemical nomencla- 

 ture (already sufficiently confused) will not be deluged. Aplones, 

 Diamerones, Dianhydes, Anames, Anoses, Aziles, Aleses, Alcinyles, 

 Metoyles, Rhizonyles, Diameraies, Synebteres, Dixerides, Udolides, 

 &c, &c, ad infinitum. But these are euphonious compared with 

 Gmelin's designations of which the following may serve as specimens : 

 Alan, Alen, Ofun, Apuk, Patakplatek, Patanafintalkanafin, and last, 

 but not least, for simple Alum, Atolantelminojafinweso ! ! 



The work is of such a nature as scarcely to allow of any extracts, 

 but we have appended a note in which Laurent explains the difference 

 between his and Dumas' ideas respecting substitution, which were by 

 many considered to be identical. 



"The notion of substitutions, if we understand thereby, as we ought to understand, 

 the replacemont of chlorine, by bromine, iodine, and fluorine, or the replacement 

 of Bilver, by copper, iron, or potassium, is as ancient as are the ideas of Richter and 

 Wenzel upon the decomposition of salts. We have known for a long time that the 

 single bodie3 displace one another mutually from their combinations, most generally 

 by exchanging equivalent for equivalent, but not unfrequently in a different 

 manner. 



We have known that chlorine, by its action upon certain organic substances, as 

 cyanhydric acid, essence of bitter almonds, wax, &o., expels a certain number of 

 atoms of hydrogen, which are replaced by an equal number of atoms of chloriue. 

 We have known that oxygen sometimes comports itself in a similiar manner, and 

 also, that in some bodies the hydrogen aet free is not replaced by its equivalent of 

 chlorine. 



Two questions prcsant themselves : 1°. Can we know a priori, whether the hy- 

 drogen set free, will or will not be replaced by its equivalent of chlorine, and how 

 much of it may be liberated without substitution ? 2°. What becomes of the chlorine 

 in the new chloro-COmpounds ; what function does it fulfil ; of what nature are the 

 compounds into which it enters, either by an equivalent, or a non-equivalent sub- 

 stitution ? 



These two questions are, we perceive, altogether independent.of each other. We 

 might discover the law presiding over substitutions, without knowing what takes 

 place within the chloro-compounds, and vice versa. 



Dumas confined himself to the first question, and under the name of the theory 

 of substitutiors (he himself remarked that he ought to have said law of substitutions) 

 he announced the two following propositions : 



1°. When we treat an organic substance by chlorine, bromine, iodine, or oxygen, 

 these bodies generally set free hydrogen, and for one equivalent of hydrogen liberated, 

 there is retained in the compound one equivalent of chlorine, bromine, iodine, or 

 oxygen. 



