IX.] CHEMISTRY OF NATURAL WATERS. 135 



III. 



CHEMICAL AND GEOLOGICAL CONSIDERATIONS. 



CONTENTS OF SECTIONS. 52. Salts of alkaline metals; proportion and sources 

 of potash ; 53. Potassium and sodium in the primitive sea ; 54. Salts of 

 lime and magnesia ; relations of chlorides and carbonates ; 55. Solubility 

 of earthy carbonates ; 56. Supersaturated solutions of carbonates of lime 

 and magnesia ; 57. Salts of barium and strontium ; solution of their sul- 

 phates ; 58. Iron, manganese, alumina, and phosphates ; 59. Bromides 

 and iodides ; the small portion of bromine and the excess of iodine in 

 saline springs as compared with the modern ocean ; 60. Probable relation 

 of iodides to sediments ; 61. Sulphates, their elimination from waters ; 

 62. Water holding a soluble sulphuret ; 63. Borates, their detection ; 

 64. Analysis of a borax-water from California ; 65. Carbonates, their 

 amount in the Caledonia waters ; 66. Intervention of neutral carbonate 

 of soda ; 67. Deficiency of carbonic acid in waters ; 68. Reactions of vari- 

 ous waters; 69. Silica, its source and its proportion; 70. Its conditions ; 

 formation of silicates ; 71. Organic matters ; 72. Geological position of 

 the waters here described ; 73. Succession of palaeozoic strata ; litho- 

 logical relations of successive formations ; 74. Quebec group, its waters ; 

 75. Sources of various classes of waters ; 76. Their relation to the forma- 

 tions ; 77. Associations of unlike waters ; changes in constitution ; 78. 

 Temperature of springs ; thermal waters ; 79. Geological interest of the 

 above analyses ; possible results of the evaporation of these springs. 



52. SALTS OF THE ALKALINE METALS. These salts abound 

 in most saline waters, and, except in the few cases in which 

 sulphate of magnesia prevails, form a large part of the soluble 

 matters present. The salts of sodium are by far the most abun- 

 dant, and the proportion of potassium-salt is generally small. 

 The chloride of potassium in modern sea-water constitutes three 

 or four hundredths of the alkaline chlorides, while in the brines 

 from old rocks, and in saline waters of the first two classes 

 alike from Germany, England, the United States, and Canada, 

 its proportion is much less, sometimes amounting to traces only. 

 In the waters of Classes III. and IV., where alkaline carbon- 

 ates appear, and even predominate, the proportion of potassium- 

 salt becomes greater. Thus of the waters of the latter class 

 ( 45), the alkalies of the Nicolet spring calculated as chlorides 

 contain 1.89 per cent of chloride of potassium, and those of 

 the Jacques-Cartier 2.95; while for the St. Ours spring the 



