muriatic acid and evaporated to dryness, left, when first macerated with muriatic acid, and afterwards perfectly lixiviated with water, 2.539 gr. of silica; which, quantity, if proportionated to the whole amount of the residue, gives, for 1000 gr. of the water, 0.04610 gr. of silica,..

T

VI. The muriatic solution obtained in V. was precipitated by sulphuretted hydrogen. After twenty-four hours, the liquid was strained off from the sulphuret of lead*; and the hydrothioic acid being expelled by boiling, the iron was again oxidised by chlorine. The liquid (a solution of muriate of ammonia being added) was now precipitated in a closed vessel, by ammonia. The precipitate was kept for further

examination.

VII.-Half of the liquid separated from the precipitate in -VI was precipitated by oxalate of potash. The oxalate of lime, when converted into sulphate, weighed 37.720 gr.; which quantity, proportionated to the whole amount of the earthy residue, gives, for 1000 gr. of the water, 136984 || sulphate of lime, equal to 0.56894 gr. of lime. Jo ng kont

VIII The liquid separated from the oxalate of lime was precipitated by ammonia and phosphate of ammonia. The ammonia-phosphate of magnesia, after washing with water containing from three to four per cent. of ammoniat, gave, after ignition, 6.139 gr. phosphate of magnesia; which, com

filter and ignited; then the filter, together with the remainder of the precipitate, was burnt and ignited; and the weight of both portions was separately ascertained.

The filter containing the sulphuret of lead was burnt, and the ashes (with an addition of carbonate of soda) being reduced before the blowpipe, the fused mass, taken from the charcoal, left, by a careful elutriation, particles of metallic lead in the mortar, which, when collected, amounted to 0.032 gr. I assume the lead to originate from the pipes or pump used for the conveying of the water; and although its quantity is very trifling, yet it deserves the attention of the managers of the Pump-room, whether a more proper material for that purpose might not be selected.

When distilled water alone is used for washing, the precipitate begins to dissolve as soon as the saline liquid is strained off, and the washing fluids are precipitated, as well by ammonia as by the saline fluid first separated.

puted for the whole amount of the residue, make, for 1000 gr. of the water, 0.22294 gr., equal to 0.08175 gr. of magnesia.

IX.-55000 grains of the mineral water were evaporated. The residue, dried at a temperature some degrees above 212°, (where, however, a dissipation of muriatic acid already took place,) weighed 114.75 gr. making for 1000 gr. of the water 2.08636 gr. It was afterwards ignited for some time, after all disengagement of muriatic acid had ceased, (in which state it weighed 110.55 gr.,) and then boiled with water and an excess of pure quicklime, in order to decompose a small portion of magnesia salt, which the mass was found to contain. The liquid was strained off when boiling, and the earthy residue on the filter was perfectly lixiviated with boiling water. The fluids obtained were precipitated, first, by muriate of barytes, then by carbonate and oxalate of ammonia. The fluid, when separated from the precipitate, gave, by evaporation and fusion, 26.46 gr. of the chlorides of potassium and sodium, which, when dissolved in water, left 0.15 gr. earthy residue, thus leaving 26.31 gr. of the chlorides for 55000 gr. of the

water.

water.

X. The solution of the chlorides was mixed with three times of their own weight of per-chloride of platinum, dissolved in The mixture was evaporated to dryness, and the residue macerated first with 38 times of its own weight of alcohol, sp. gr. 0.84 at common temperature, (the quantity which I found the crystallized sodio-perchloride of platinum to require for solution at 60° temp.) The alcoholic solution being decanted, the residue was boiled with a new portion of alcohol. The insoluble potassio-perchloride of platinum being separated, washed with alcohol, and dried at 212°, amounted to 6.378 gr. equal to 1.96130 gr. of chloride of potassium, which quantity gives for 1000 gr. of the mineral water 0.03566 gr. equal to 0.02256 gr. of potassa.

The quantity of chloride of sodium obtained from 1000 gr. of the mineral water amounts thus to (26.31-1.9613) 0.44270 gr. equal to 0.23591 gr. 55 of soda.

XI. The slight precipitate, adhering to the sides of the bottles which the mineral water had been contained in, was dissolved by muriatic acid. The solution diluted with the rest of the mineral water left in the bottles (1535 gr.) was digested on the earthy residue obtained in IX. The acid solution was evaporated to dryness, and re-dissolved in muriatic acid and water. Filtered off from the remaining silica, it was precipitated by ammonia. This precipitate, together with the precipitate obtained in VI. were dissolved in an excess of muriatic acid, and precipitated by bi-carbonate of ammonia. The weight of alumina and peroxide of iron thus obtained from 112535 gr. of the mineral water, was found to be, after ignition, 0.499 gr., 0.459 of which, when dissolved in muriatic acid, and decomposed by caustic soda, left 0.241 gr. of peroxide of iron, leaving for the alumina 0.218 gr.

By proportionating these quantities, we obtain for 1000 gr. of the mineral water 0.00215 gr. of alumina, and 0.00237 gr. of per-oxide of iron, equal to 0.00213 gr. of the protoxide.

Thus, recapitulating the foregoing results, the solid ingredients contained in 1000 gr. of the Bath water amount to

which quantity coincides nearly with 2.08636 gr., the weight of the dry residue obtained from 1000 gr. of the mineral water, which had, however, lost part of its muriatic acid.—(IX.)

If we arrange the above ingredients into binary combinations, according to the predominant chemical affini

bl

t

ties, (in which state they will exist in the mineral water, at least in the greatest proportions,) we find the Bath water

In distributing the acids and bases, there remains a surplus "of 0.01827 of carbonic acid. The processes by which the different bases were separated being more complicated, it is to be expected that the loss which they sustained is proportionably greater than with the acids. Besides, the determination of the carbonic acid itself is less certain than that of the other constituents, on account of the comparatively small quantity employed for the experiment, and the simplicity in transferring measure into weight.

The re-action which tincture of galls produces in the mineral

*The results of this analysis differ, at the first appearance, very much from those obtained by Dr. Scudamore, the cause of which is the different theoretical view which the Doctor has followed in computing the binary combinations. Having transferred the data of Dr. Scudamore into equivalents, according to the greatest mutual affinities, I subjoin a table of his analysis, computed for the same quantity of the mineral water (34.659 cub. inch.), in order to facilitate a comparison.

1 pint.

water, just drawn from the pump, is slighter than we could anticipate it to be, according to the proportion of iron found by the analysis: the cause of which, however, is, that a part of the iron is precipitated instantaneously, when the mineral water, by pumping and pouring into the tumblers, mixes with the atmospheric air. It is therefore merely suspended in a very minutely divided state, (probably in the form of a silicate,) and has no effect on the re-agent, which is only acted upon by that portion of iron which is present in a state of solution.

2 A

Captain F. Forbes of Winkfield Place, Windsor Forest, discovered, some time ago, two mineral springs on his estate; one, the analysis of which is stated under A., in the immediate neighbourhood of his mansion; the other, mentioned hereafter under B., at some distance. Both these mineral springs, belonging to the magnesio-saline class, have since been used, as I am informed, by a great number of patients; and the good effects which have been observed from their use have induced Captain Forbes to build a pump-room for the accommodation of the public.

The mineral waters which were sent to my laboratory for chemical examination were colourless, almost perfectly transparent, and without smell. If exposed to the air in an open vessel, they very soon covered the sides of the glass with a precipitate of carbonate of lime. Boiling produces a very copious earthy precipitate. Slightly reddened litmus paper is turned by them into blue; the carbonic acid gas, which they yield by boiling, must therefore be considered entirely to exist in them in union with the earthy carbonates, forming bicarbonates. Q

Both mineral waters were examined in a similar way to the Bath water; and the results of their analysis gave their constituents as follows: