The composition of Sea-Water has been variously stated by different chemists, not only with regard to the proportions of the salts which it holds in solution, but with regard even to the ingredients themselves.

According to Lavoisier, it contains muriate of soda, muriate of magnesia, and muriate of lime, sulphate of soda, sulphate of magnesia, sulphate and carbonate of lime. The proportions he assigns are, in a pound of water, (French weights) 126 grains of muriate of soda, 14¾ grains muriate of magnesia, 23 grains muriate of lime mixed with muriate of magnesia, 7 grains of sulphate of soda and sulphate of magnesia, and 8 grains of sulphate and carbonate of lime.

It is well-known as a fundamental principle in statics, that “Two pressures, represented in direction and quantity by “two adjoining sides of a parallelogram, are equivalent to one “represented in direction and quantity by the diagonal “which passes through the point at which these sides meet.” A demonstration of this proposition, that shall be at once sufficiently concise, and sufficiently elementary, to admit of its being with propriety introduced into a course of academical instruction, has been hitherto, so far as I know, a desideratum. The following may perhaps be found to possess that advantage.

My Dear Brother,

The inclosed account was drawn up at the request of Robert Græme, Esq. when all the circumstances were fresh in my own recollection, and that of all with whom I had occasion to confer on the subject. Since you requested me to send you a correct copy of the whole case, I have renewed my inquiries among the friends of the young woman, and submitted my account to several persons, who were most capable of supplying any omissions, or correcting any mistakes. I can confidently vouch for the general accuracy of the statement; but would not wish its credibility to rest entirely on my single testimony.

The analysis of Mineral Waters has always been considered as a difficult operation. Numerous methods are employed to discover their ingredients, and estimate their quantities, many of which are liable to errors. This diversity of method itself is a source of discordant results. And to those not familiar with such researches, it presents the difficulty often of determining what process is best adapted to discover a particular composition. Hence the advantage of a general formula, if this could be given, applicable to the analysis of all waters. The views which have been stated in the papers, connected with this subject, which I have had the honour of submitting to the Society, have suggested a method which appears to me to admit of very general application, and to be simple, not difficult of execution, nor liable to any sources of error but what may be easily obviated. The principles on which this method is founded, and the details of the process itself, form the subject of the following observations.