VIII. 



ON LIMESTONES, DOLOMITES AND 

 GYPSUMS. 



(1858-1866.) 



The results of the author's researches on the chemistry of the salts of lime and 

 magnesia, undertaken with reference to the theory of mineral-waters and the origin of 

 calcareous and magnesian rocks, were first announced in the American Journal of Sci- 

 ence for July, 1858, and subsequently more at length in an essay in that journal for 

 September and November, 1859. This paper, which extended over thirty-six pages, 

 was divided into five parts, of which the first treats of the action of solutions of bicar- 

 bonate of soda on the soluble salts of lime and magnesia ; the second on the reactions 

 between solutions of bicarbonate of lime and the sulphates of soda and magnesia ; 

 the third describes the production of the double carbonate of lime and magnesia 

 (dolomite) ; the fourth discusses various facts in the history of gypsums, dolomites, 

 magnesites, and limestones ; and the fifth treats of the mode of formation of these 

 rocks. The continuation of the subject in the same journal for July, 1866, occupies 

 nineteen pages, and includes researches on the hydrated double carbonates of lime 

 and magnesia, on supersaturated solutions of these two carbonates, and on the alleged 

 decomposition of gypsum by dolomite, besides further experiments on the artificial 

 production of dolomite. 



Allusions to some of the results obtained are made in paper IV., and many more 

 of the results are embodied in the one on Natural Waters (IX.), while in XIII. will be 

 found a brief summary of the results so far as the origin of dolomites and m;:. 

 limestones is concerned. I have thought it well to reproduce in the present collection 

 some few selections from the fifth part of the essay of 1859, and to preface them by a 

 translation of parts of a letter written to Elie de Beaumont and printed in the Comptes 

 Rendus of the French Academy of Science for June 9, 1862, and subsequently in the 

 Canadian Naturalist. 



FROM THE COMPTES RENDUS OF THE FRENCH ACADEMY 

 OF SCIENCES, JUNE 9, 1862. 



ON the 28th of October, 1844, a memoir was deposited with 

 the Academy by the illustrious Cordier. Being in a seal.-d 

 packet, its contents remained unknown until after his death, 

 when, at the request of his widow, the seal was broken, and 

 the paper, which bears the date of October 22, 1844, was first 

 made public in the Comptes Rendus of the Academy for Febru- 



