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Some are much surprised that I should, as they think, venture to oppose the conclusions of Newton: but here there is a mistake. I do not oppose Newton on any point; it is rather those who sustain the idea of action at a distance that contradict him. Doubtful as I ought to be of myself, I am certainly very glad to feel that my convictions are in accordance with his conclusions. At the same time, those who occupy themselves with such matters ought not to depend altogether upon authority, but should find reason within themselves, after careful thought and consideration, to use and abide by their own judgement. Newton himself, whilst referring to those who were judging his views, speaks of such as are competent to form an opinion in such matters, and makes a strong distinction between them and those who were incompetent for the case.

But after all, the principle of the conservation of force may by some be denied. Well, then, if it be unfounded even in its application to the smallest part of the science of force, the proof must be within our reach, for all physical science is so. In that case, discoveries as large or larger than any yet made may be anticipated. I did not resist the search for them, for no one can do harm, but only good, who works with an earnest and truthful spirit in such a direction. But let us not admit the destruction or creation of force without clear and constant proof. Just as the chemist owes all the perfection of his science to his dependence on the certainty of gravitation applied by the balance, so may the physical philosopher expect to find the greatest security and the utmost aid in the principle of the conservation of force. All that we have that is good and safe, as the steamengine, the electric telegraph, &c., witness to the principle,-it would require a perpetual motion, a fire without heat, heat without a source, action without reaction, cause without effect, or effect without a cause, to displace it from its rank as a law of

nature.

XXXVI. On the Chemical Composition of the Waters of the St. Lawrence and Ottawa Rivers. By T. STERRY HUNT, of the Geological Survey of Canada*.

THE study of the chemical composition of the waters of great rivers offers many points of interest, whether considered in relation to the disintegration and solution of existing rock formations, the formation of new deposits, or the part which these waters play in the economy of animal and vegetable life.

*From the unpublished Report of the Survey for 1854. Communicated by the Author.

The following analyses were made by me, three years since, of the waters of the St. Lawrence, and its great tributary the Ottawa, and will serve to illustrate several important facts hitherto but little noticed.

The waters were collected at the close of the winter season, after three or four months of frost, and before the melting of the snows, and were taken at some distance from the shores, where a rapid current prevented the ice from forming. The water of the Ottawa was collected on the 9th of March, 1854, at St. Anne, near the head of the island of Montreal; the temperature of the water here flowing from beneath the ice was 33° F., that of the air being the same. The water was entirely free from all sediment, and had a pale amber-yellow colour, very distinct in masses of 6 inches; when heated, this colour deepens; and by boiling, a bright brown precipitate appears, which, when the water is evaporated to one-tenth, is seen to consist of small, brilliant, iridescent scales. These are not gypsum, of which the water does not contain a trace, but consist of silica with lime, magnesia, carbonic acid, and organic matter. Meanwhile the water becomes much more highly coloured, and exhibits an alkaline reaction with test-papers. When the above precipitate is boiled with a dilute solution of potash, it is in part dissolved, and the alkaline liquid acquires a deep brown colour, which is rendered paler by an excess of acetic acid. Acetate of copper yields no precipitate with the acidulated liquid; but on subsequently adding carbonate of ammonia and applying heat, a minute white precipitate appears to indicate the crenic acid of Berzelius. This, however, corresponds to but a small portion of the organic matter present in the water, where it probably exists chiefly in the form of humic acid, or some analogous compound.

The recent water, mingled with hydrochloric acid and a salt of baryta, is at first clear, but after an hour becomes turbid from the precipitation of a trace of sulphate. With nitric acid and nitrate of silver, a slight milkiness from the presence of chloride is perceptible. The chlorine and sulphuric acid were determined upon four litres of the water, reduced by evaporation to a small volume, and acidulated with nitric or hydrochloric acid. The precipitate obtained with nitrate of silver and a few drops of nitric acid in the evaporated water, was scanty and reddish coloured; after twelve hours of repose, it was separated, washed, and dissolved on the filter by caustic ammonia; from the coloured liquid thus obtained, the chloride of silver was thrown down by a considerable excess of nitric acid, while an organic salt of silver remained in solution.

The brown matter precipitated by boiling being dissolved in hydrochloric acid, the solution was decolorized by boiling with

chlorate of potash. By evaporation a portion of silica separated, and the solution gave with ammonia a colourless precipitate, which was in great part soluble in potash, and contained alumina; redissolved in hydrochloric acid, however, it gave with a sulphocyanide evidence of the presence of peroxide of iron, and with molybdate of ammonia an abundant yellow precipitate, indicating phosphoric acid. Heated on silver foil with caustic potash, the aluminous precipitate gave a distinct manganese reaction.

When the Ottawa water is evaporated to dryness in a platinum capsule with an excess of hydrochloric acid, and the residuum treated with dilute acid, there remains a large amount of silica, coloured brown by organic matter. It becomes white by ignition, and is then perfectly pure, and equals one-third of the whole solid matters present. A portion of the water was evaporated to one-fortieth and filtered; when further evaporated to onefourth, it deposited on the platinum vessel an opake film, which was but partially soluble in hydrochloric acid. The liquid was now dark brown, and reddened turmeric-paper. Evaporated to dryness and ignited, the portion soluble in water was strongly alkaline to test-papers, and perceptibly so to the taste. The insoluble portion was decomposed by hydrochloric acid without effervescence, pulverulent silica separated, while the acid retained in solution a portion of lime, but no magnesia.

The residue from the evaporated water is deep brown in colour; when ignited, it diffuses an agreeable vegetable odour, and a little carbon remains. The water was not examined for nitrates; but the absence of any deflagration during the ignition showed, that, if present, they were in small amount. The season at which the water was collected, at the close of a long winter, could moreover scarcely be supposed to favour the presence of nitrates. The following numbers are deduced from two or more concordant determinations made upon two and four litres of water, and calculated for ten litres, or 10,000 grms. :

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The amount of silica remaining dissolved in the water, evaporated to one-twentieth, was found in two experiments to be 0.019 Phil. Mag. S. 4. Vol. 13. No. 86. April 1857.

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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.

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The water of the St. Lawrence was collected on the 30th of March, 1854, on the south side of the Pointe des Cascades, Vandreuil. 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 concentrated 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 molybdate of ammonia; less abundant, however, than from the same volume of the Ottawa water. The following results were obtained from 10,000 parts:

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When evaporated to one-fortieth, the water still contains in solution silica and lime, but no magnesia; the amount of silica thus retained was 0.750, and the lime equalled 0·050 of carbonate for ten litres. The proportions of sulphuric acid and chlorine are much larger than in the Ottawa water, but are insufficient to neutralize the alkaline bases; so that the lime in the evaporated water must exist in combination with organic acids, or more probably as a soluble silicate. I subjoin the calculated results of the analysis for 10,000 parts, the lime and magnesia being represented as carbonates :

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The presence of silicate of lime in an alkaline solution is constantly met with in the analysis of alkaline mineral waters. have signalized it in the Varennes, Chambly, and Fitzroy springs; and Dr. J. L. Smith has remarked a similar fact in his examinations of the thermal springs of Asia Minor*. I have found that if such a water is evaporated to dryness with the precipitated carbonates in suspension, the whole of the silica is separated in combination with the earthy bases; but if the earthy carbonates at first thrown down by boiling are removed, there separates upon subsequent evaporation a silicate of lime, which does not, however, contain the whole of the dissolved silica, a portion remaining as an alkaline silicate.

Bischoff has shown that artificial silicate of lime, which is somewhat soluble in water, is decomposed by carbonate of mag

American Journal of Science (2), vol. xii. p. 377. For similar observations see also Bischoff's 'Chemical Geology,' English edition, vol. i. p. 5.

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