The following circular letter has since been issued by the President of the Convention, and addressed to the leading Pharmaceutists throughout the Union:—
NEW YORK, November 25, 1851.
SIR:—At a meeting of Delegates from the Colleges of Pharmacy of the United States, held in this city on the 15th of October, 1851, the following preamble and resolutions, explanatory of themselves, was offered, and, after a free and full discussion, unanimously adopted:—
[Here follow the preamble and resolutions introduced by Messrs. Proctor, Restieaux, and Coggeshall.]
The objects set forth in the above, I trust, will meet the hearty approbation of yourself and the apothecaries of your place, and lead to the formation (if not already in existence) of such an Association as will co-operate in the furtherance of the proposed association.
Our medical brethren have, as you are doubtless aware, an organization, similar in character, holding its sessions annually, in which all matters pertaining to their profession are fully discussed—the beneficial effects of which are already apparent, though the association has been in existence but a few years.
They cannot give to the subject of Pharmacy the attention it requires and deserves, neither is it a matter legitimately falling under their cognizance, but belongs to Pharmaceutists themselves.
The medical profession and the community at large rightfully look to us for the correction of any existing abuses, the advancement of the science, and the elevation of the business of an apothecary to the dignity and standing of a profession.
To this end we invite you to the formation of such Associations, in view of the Convention, to be held in Philadelphia, on the first Wednesday of October, 1852.
Communications intended for said Convention may be addressed to William Proctor, Jr., Philadelphia, George D. Coggeshall, New York, or S. M. Colcord, Boston.
Any communication touching the subject of the above letter will be cheerfully responded to by the President of the Convention.
C. B. GUTHRIE, M. D.,
President Convention of Colleges of Pharmacy.
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NEW YORK JOURNAL OF PHARMACY. FEBRUARY, 1852.
ON THE PREPARATION OF PURE HYDRATE OF POTASH AND CARBONATE OF POTASH. BY HENRY WURTZ, A. M.
In preparing pure potash compounds, it is highly necessary, especially in order to avoid the possibility of the presence of soda, to select, as a starting point, some compound of potash which differs considerably in solubility from the corresponding soda compound. Either the bitartrate or the sulphate, therefore, is usually preferred.
The bitartrate is ignited; the carbonaceous mass, washed with water, and the solution of carbonate of potash, thus obtained, diluted and boiled with slack lime, in the usual way, in an iron kettle; the solution of hydrate of potash, thus obtained, is boiled to dryness, and the alcoholic solution of the residue evaporated in silver dishes, to obtain what is denominated alcoholic potash. This product should be, and most usually is, entirely free from sulphate of potash and chloride of potassium, since it is easy to crystallize the bitartrate free from these salts.
But an almost invariable accompaniment of this alcoholic potash is a trace of silicate of potash. The solution may assume no cloudiness on the addition of solution of chlorohydrate of ammonia, or upon addition of an excess of chlorohydric acid, and afterwards an excess of ammonia; but on adding excess of chlorohydric acid, and evaporation to dryness in a platinum {34} capsule, the aqueous solution of the residue will be found to have flakes of silica floating in it. Very few specimens that I have met with have stood this test. It is to be inferred that the soluble silicates of potash are not wholly insoluble in alcohol; but a question arises concerning the source from whence the silica is so frequently derived. It may be from the lime used, in some cases, or from silicium contained in the iron of the kettles employed. I am enabled to state, in addition, that of many specimens of commercial carbonate of potash which I have examined, some of which purported to have been prepared from cream of tartar by the method above alluded to, none have been found entirely free from silica. I have even found traces of this impurity in crystals of commercial bicarbonate of potash.
This constant contamination of potash, and carbonate of potash with silica, being a very important matter in consideration of the frequent use of these two substances in chemical analysis, I have been induced to devise a means of separating the silica from the carbonate. This I have accomplished by the use of carbonate of ammonia.
An aqueous solution of the carbonate which is to be freed from silica is evaporated to dryness on the sand bath (best in a sheet iron dish), adding from time to time lumps of carbonate of ammonia. The silicate is thus converted into carbonate, and on dissolving the residue of the evaporation in water, the silica appears in the form of flakes floating in the liquid, and may be separated by filtration. This solution of carbonate of potash, free from silica, may now be used for the preparation of pure hydrate of potash, taking care to use lime which is also free from silica.