Alexander Marcet

“ The accurate analysis of a mineral water, although attended with considerable difficulty and labour, must be allowed, in a general point of view, to be an object of so little importance, that unless there be some interesting medical question to investigate, or some new analytical methods to point out in the course of the inquiry, it may be questioned whether researches of this kind are worth the time and attention which they require, or deserve to be placed amongst the records of natural science. ”

“ If a solution of potash be added to the washed precipitate, previous to the application of heat, a strong smell of ammonia arises, and the oxyd passes to a dark greyish colour, showing that the precipitate is a triple salt of oxalic acid, iron, and ammonia. ”

“ If oxalat of ammonia be added to a solution of sulphat of iron, a bright yellow colour is produced, and presently after this a copious white precipitate appears, which, in subsiding, assumes a pale lemon colour. If at the moment the cloud is forming, the vessel be scratched with any pointed instrument, white lines appear, as in the precipitation of magnesia from carbonic acid by phosphoric acid. ”

“ Before drawing any ultimate conclusion respecting the contents of the water and the proportions of its ingredients, I found it necessary to ascertain the quantities of sulphuric and muriatic acids which it contained, in order to enable me to try how far these quantities might coincide with the conclusions obtained by the separation of the basis, and also to assist me, as will be seen hereafter, in forming certain inferences with regard to the alkaline salts. ”

“ By this last operation a portion of the salt was decomposed and rendered insoluble in water, in spite of which the remainder still exhibited signs of acidity. The clear solution of this mass being divided into two equal portions, one of which was precipitated by succinat of ammonia, and the other by nitrat of basytes, yielded 4,5 gra. of ignited alumine for 21 grs. of ignited sulphat of barytes. From which it may be inferred, that the 8,8 grs. of ignited alumina found in a pint of the water, were combined with a quantity of acid equal to 17,7 grs. of ignited sulphat of barytes. ”

“ When submitted to chemical analysis, it yields a quantity of iron, but no lime, nor alumina, nor any other earthy matter soluble in an acid. Close to the spring, this sand contains some traces of sulphuric acid, but not at a distance from its it is evident therefore that the sand-rock is not the medium through which the spring is impregnated. ↑ Solutions of sulphat of iron and sulphat of alanine, though made from there salts in their crystallized state, have, like acids, the power of imparting s red colour to litmus. ”

“ D. On applying heat to a portion of the water just uncorked, and boiling it quickly, till it was reduced to one half or even one third of its original bulk, no precipitation whatever took place; but on continuing the evaporation, a white feathery crystalline substance appeared on the surface of the fluid, and on pushing the process still further, a saline matter of a pale yellowish green colour appeared, which continued to increase till the whole was reduced to a dry yellowish mass. ”

“ This method, though affording a very useful means of discrimination, must obviously be liable to inaccuracy as to proportions, when very minute portions of silica are to be separated from considerable quantities of alumine. This however was the process to which I trusted on a previous occasion (IX. 2) , to free the alumina from the silica which was mixed with it. ”

“ And in comparing a quantity of residue with a corresponding portion of the water, the average proportion of 80,5 grs. for each pint (§ VI. 2) is always assumed as the standard of comparison. ↑ The acetic acid, as well as the nitric, is said to be incapable of dissolving any Iron, which has been peroxydated by the process just described. In this instance a few particles of oxyd were taken up by the acid ”

“ Chenevix, is much more appropriate than acids, because if an excess of acid be incautiously added, the precipitate is re-dissolvsd; whilst with muriat of ammonia, an excess of the test is attended with no inconveniences. ↑ The presence of silica was also shewn, and its quantity attempted to be ascertained by the following process. ”

“ Kirwan, and which I obtained myself on a former occasion (See the Analysis of the Brighton Chalybeate.) ↑ It is scarcely necessary again to observe, that the sulphat of alumine contained it the water does not appear to exist there in the state of alum ; but it is perhaps better to express the quantity of alumine by the quantity of alum which it would form, as the crystallised state of a salt affords a much more precise standard of comparison. ”