243 Mr. T. S. Hunt on the Chemical Composition of 



and 0*020 grm. for four litres, thus giving a mean for ten litres 

 of 0"046 grm. silica retained in solution, while the amount of lime 

 remaining dissolved in the water thus evaporated was equal to 

 0'023 grm. for the same quantity. 



The quantities of chlorine and sulphuric acid in this water are 

 sufficient to neutralize only about one-half of the alkalies present; 

 the remaining part must, like the lime and magnesia, be regarded 

 *as existing in combination with silica, carbonic acid, or the 

 organic acids whose presence we have indicated. To show the 

 relations of the bases to the chlorine and sulphuric acid, we have 

 in the following Table calculated the earthy bases and the excess 

 of alkalies as carbonates, thus giving necessarily an excess in the 

 sum of the weights over that of the ignited residue. 



•6116 



The water of the St. Lawrence was collected on the 30th of 

 March, 1854, on the south side of the Pointe des Cascades, Van- 

 dreuil. It was clear and transparent, and, unlike the Ottawa 

 water, exhibited no colour in masses several inches in thickness. 

 The recent water gives a considerable precipitate of sulphate of 

 baryta, and a distinct one of chloride of silver with the proper 

 tests. When boiled it lets fall an abundant precipitate, which, 

 unlike that from the water of the Ottawa, incrusts the vessel. A 

 little yellowish flocculent matter remains suspended in the con- 

 centrated water, which is only slightly coloured, and the dried 

 residue contains much less organic matter than the previous 

 water. The residue from two litres dissolved in hydrochloric 

 acid, sufficed to give distinct reactions of iron and manganese. 

 The ammoniacal precipitate from this solution was in great part 

 soluble in potash, and was alumina. From a second portion of 

 two litres a precipitate of phosphate was obtained with molyb- 

 date of ammonia; less abundant, however, than from the same 

 volume of the Ottawa water. The following results were obtained 

 from 10,000 pai-ts:— 



