MESSRS. FOULGER & SON. Opium Smyrnæum - Aloe Barbadensis Aloe capensis Aloe hepatica-Gummi acacia (best)-Ditto (second) Gummi Indicum-Cetraria Islandica-Chondrus crispus-Aurantii bacca -Colocynthidis poma-Petroleum Barbadense-Sapo Castiliensis-Oleum macis (as imported)-Sanguis Draconis (best)-Ditto (second)-Ammoniacum, in lachrymis.

MR. SMITH, Hampstead.-Phytelephas Macrocarpa (vegetable ivory). MR. WHEATON, Sol's Row, Hampstead Road.-Phytelephas Macrocarpa (vegetable ivory).

MR. MORSON.--Ergotised Wheat.

MR. LUCKOMBE, Snow Hill.-Agaricus-Cardamoms (Java)-Ditto (Ceylon)-Ditto (Malabar, decorticated)-Cuscas or Vitiver.

MR. SQUIRE. Iodide of Iron, in crystals - Extractum Conii - Liquor Conii.

MR. F. DIXON, Ash, Kent.-Melilotus cærulea (in seed).

MR. G. W. SMITH.-Cycas revoluta (unimpregnated fruit)-Amygdalus communis (fructus et folia).

APPARATUS.

MR. HUDSON.-Electrical Machine and Apparatus.

MR. FREDERICK BELL.-Four Evaporating Basins (Sevre ware). MR. BUCKLES, Peterborough.-CHINESE MORTAR AND PESTLE, represented in the following wood-cut:

OBSERVATIONS ON ATOMIC WEIGHTS

SUGGESTED BY

SOME RECENT CONTINENTAL INVESTIGATIONS.

IN 1815, Dr. Prout published (anonymously) in the sixth volume of the Annals of Philosophy (page 321) a paper " On the Relation between the Specific Gravities of Bodies in their Gaseous State, and the Weights of their Atoms," in which he threw out the idea that the atomic weights of bodies were multiples by a whole number, of the atomic weight of hydrogen. This notion appears to have been adopted by Dr. Thomas Thomson, the Regius Professor of Chemistry in the University of Glasgow, who undertook a series of analytic inves tigations to prove its accuracy. The results he has published in his "Attempt to establish the First Principles of Chemistry by Experiment," in 2 vols., published in 1825.

But the correspondence between Prout's hypothesis, and the results of Thomson's experiments, was so startlingly precise, while the analyses of other, especially continental, Chemists, differed so considerably from those of Thomson and his pupils, that great distrust has prevailed amongst Chemists as to the accuracy of his statements, and at the present time, there are few Chemists, whether British or Continental, who have supported Prout's hypothesis, or adopted Thomson's atomic weights. The results of the earlier experiments of Berzelius on the atomic weight of lead, confirmed by his later ones in 1830+, appear in complete contradiction to Prout's notion, which, therefore, has been almost universally rejected.

In 1833, the late Dr. Turner (Phil. Trans. 1833) observed that "Dr. Prout's hypothesis, as advocated by Dr. Thomson, that all atomic weights are simple multiples of that of hydrogen, can no longer be maintained;" and he further asserted that the hypothesis was "at variance with the most exact analytic researches which have been conducted."

In 1839, Mr. Richard Phillips (Phil. Trans, for 1839, p. 35) published some experiments, from which he inferred, "that no material, and scarcely even any appreciable error can arise from considering the equivalents of hydrogen, oxygen, azote, and chlorine, as 1, 8, 14, and 36, respectively," thus confirming Prout's hypothesis.

*Thomson's work was made the subject of a most bitter, abusive, and unfair criticism by Berzelius in his Arberetälre for 1837. See the Philosophical Magazine, N.S. vol. iv., page 450, 1828. For Thomson's reply, see the same work, vol. v. 1829.

+ Poggendorff's Annalen, vol. xix, page 310 to 315, 1830.

In 1841, MM. Dumas and Stas published (Annales de Chimie et de Physique, t. 1me., 3 série, p. 5) an elaborate set of experiments to determine the atomic weight of carbon, the results of which appeared to show that the number adopted by Prout for this element was correct. Assuming 100 to be the atomic weight of oxygen, 75 will be (according to Prout and Thomson) the number for carbon. Now the experimental results of Dumas and Stas gave 74.982 as the atomic weight for graphite, and 75.005 that for diamond, numbers which most closely approximate with that of Prout.

Shortly afterwards MM. Erdmann and Marchand (Pharmaceutisches Central Blatt für 1841, p. 462; also Philosophical Magazine for Oct. 1841, p. 332-3) undertook a series of experiments on the same subject, with results confirmatory of those of Dumas and Stas. The mean of their experiments on diamonds and graphite give 75.07 as the atomic number for carbon; and they adopt 75 as the true one.

About the same time, however, there appeared a paper " On the Atomic Weight of Carbon," by MM. Redtenbacher and Liebig (see Phil. Mag., vol. xix., p. 210, Sept. 1841), in which the authors declare that the hypothesis, that the atomic weights of simple bodies are multiples of that of hydrogen by whole numbers, is quite unfounded; and assert that the true atomic weight of carbon is 75.854.

In the last number of the Philosophical Magazine (November, 1842) is an extract of a letter from Berlin to Mr. Francis, stating that "MM. Marchand and Erdmann are at present engaged in a series of researches which seem to prove that Prout's idea, that all atomic weights are multiples of that of hydrogen, is correct. They have as yet examined only the following bodies:

In consequence of the difference of opinion which has existed, and still prevails, to a certain extent, among Chemists, we have thought it better to defer, for the present, the publication of a table of equivalents. When the doubtful points have been satisfactorily decided, we shall take the earliest opportunity of publishing the result.

ILLUSTRATIONS OF THE PRESENT STATE OF
PHARMACY IN ENGLAND.

BY RICHARD PHILLIPS, F.R.S., &c.

Honorary Member of the Pharmaceutical Society.

BEFORE I proceed to state the results of the additional experiments which I have performed in reviewing the present state of Pharmacy, I shall offer a few remarks on the note which you have appended to my observations, on the strength of nitric acid.

You state that some of the most extensive manufacturers of mineral acid assert, that nitric acid of sp. gr. 1.5 is practically objectionable as an article of commerce, being generally a coloured acid, and having a tendency to assume a still deeper colour by keeping. I must confess that my experience does not warrant these conclusions; I have kept acid of this degree of strength, possessing a slight yellow tint, even in a flint glass bottle, for many months, I believe, indeed, for some years, without observing any increase in the depth of its colour. Admitting, however, for a moment, that the colour by long keeping becomes more intense, and that the acid is then "practically objectionable as an article of commerce," let me enquire what right the Chemist has to substitute an article of commerce for one of the Pharmacopoeia? The college do not require a colourless acid; but if the public do, let them have it, but do not permit a medicine to be raised or reduced in strength to suit the fancy of those who wish for a colourless acid.

Potassa Carbonas is the preparation which I shall next notice. The preparing of this, I need hardly state, is extremely simple. Among the college tests are non-precipitation by chloride of barium or nitrate of silver, after saturation with nitric acid; and also, that it should then give no precipitate on the addition of carbonate of soda.

The specimen which I first procured gave, after saturation with nitric acid, 5.5 per cent. of chloride of silver, equivalent to nearly 3 of chloride of potassium, and 2 per cent. of sulphate of barytes, denoting 1.5 of sulphate of potash; by adding ammonia and its carbonate, there were obtained small quantities of alumina or silica, and carbonate of lime. The proportion of water which the sample contained, I omitted to determine; but supposing it not to have contained more than the proper quantity, amounting to 16 per cent., we may reckon that this article consisted of about

I tried only one specimen more of this salt, for the state in which it is generally met with, will be sufficiently indicated by that of the different samples of liquor potassæ, presently to be noticed. The second specimen contained scarcely a trace of sulphate of potash, but it yielded, after saturation with nitric acid, 2.9 per cent of chloride of silver, equivalent to 1.5 of chloride of potassium. In other respects it appeared to be of good quality.

Liquor Potassa Carbonatis. As this preparation is a mere solution of 20 ounces of carbonate of potash in a pint of water, it is hardly to be expected that any material deficiency should be found in it, except such as has been already noticed as existing in the carbonate itself. This, however, was far from being the case; the specific gravity of this solution should be 1.473, that of the first specimen which I obtained was only 1.426, and I find, by direct experiment, that supposing the carbonate of potash to have contained only the usual quantity, or 16 per cent. of water, this preparation must have been obtained by dissolving about 18 ounces of it in a pint of water; the second specimen of liquor potassæ carbonatis which I procured was still more dilute, its specific gravity being only 1.358, and this must have been prepared, allowing the usual quantity of water in the carbonate of potash, by adding scarcely 14 ounces of it, instead of twenty to the pint of water.

Liquor Potassa. This preparation, although not so simple as the last, is yet not sufficiently complex to admit of any easy explanation when discrepancies occur. The directions are to take fifteen ounces of carbonate of potash, eight ounces of lime, and a gallon of boiling distilled water; the carbonate of potash is to be dissolved in half of the water, the lime to be slacked by a little of the rest, and the remainder is to be added to the slacked lime and solution of carbonate of potash. The clear liquor, after standing, is to be poured off.

Among the properties which it is stated this solution should possess, are the following:-its density, 1.063; when saturated with nitric acid, chloride of barium, or nitrate of silver, should occasion but slight precipitation.

I repeat, that one would imagine that the directions for this preparation were sufficiently simple, and the tests of its purity of easy application enough to ensure an equality of strength, of course always excepting, with regard to its strength, the different degrees of impurity which the carbonate itself may contain, and these are not likely to influence the density of the preparation, which, as already stated, should be 1.063. When the solution is of this specific gravity, I find, both by evaporation to