Gorham on Chemical Science, 349 



some animadversion, thcThomsonian theory of semi-combustion, 

 upon which we have formerly expressed our opinion. In this 

 part of his book Dr. Gorham has also wasted some pages in 

 detailing the absurd speculations respecting the absolute zero, 

 placed by Dr. Irvine at 700°., and by Mr. Dalton at 6150°. 

 below 0, this small discrepance being of little importance, it 

 would seem, in such inquiries. There is also much that might 

 have been omitted in relation to the capacities of bodies for 

 heat; but we can forgive these exuberances, as they lead to 

 a tolerable compendium of Sir H. Davy's researches on flame, 

 and to an exposition of those inimitable investigations which 

 ended in his discovery of the safety lamp. 



In Dr. Gorham's chapter on some points of chemical theory, 

 he adverts to the imperfections of all systematic arrangements 

 of the subjects of Chemistry, and to the difficulties which 

 beset the writer in concisely setting forth his materials without 

 frequent repetition, or more blamable omission of facts small 

 in themselves but important in association. " If," says he, 

 " we commence with the principles of the science, its laws 

 can be demonstrated only by a reference to the mutual actions 

 of bodies still unknown; and if individual substances be first 

 described, the general terms which have been appropriated to 

 classes of facts must be employed, and frequently but imper- 

 fectly explained." Of these difficulties, and of many others, 

 those who are at all conversant with chemical writers, must be 

 amply aware, and, in the present state of the science, we see 

 little probability of their removal, or even of their material 

 diminution. Taking all things into the account, we are of 

 opinion that Dr. Gorham has himself followed one of the least 

 exceptionable plans of arrangement; namely, that which, after 

 having discussed the general laws of chemical changes, pro- 

 ceeds to the history of elementary bodies, and of their mutual 

 combinations in inorganic nature, and, ultimately, to their com- 

 plex arrangements in the animal and vegetable world. We 

 are quite aware that this plan is not very philosophical, but 

 upon such a subject we willingly sacrifice logical accuracy to 

 perspicuous detail, and consider that as the best arrangement, 

 which most easily enables the student to retain, compare, and 

 apply the infinitely numerous, diversified, and scattered facts 

 of this endless branch of natural knowledge. 



In adverting to the analogies between the elementary sub- 

 stances, Dr. Gorham has struck out nothing new, and has not 

 been peculiarly happy in retailing the opinions of others; che- 

 mical writers indeed generally misemploy their own and their 

 readers' time, in entering upon the abstract philosophy of their 

 science, and would fill their paper more advantageously in 

 extending practical details, and describing the minutiae of ma- 

 nipulation. Could we see a System of Chemistry from the pen 



