the primitive ones in this crystal, which is very small, and partly imbedded in its gangue, completely prevents me from determining the nature of the three different retrogradations, to which they owe their existence, (To be continued in our next.) XIII. On Detonating Silver. By Mr. DESCOTILS*. R. Figuier, prof. of chemistry at the Pharmaceutical Fulminating School at Montpellier, has lately written to the authors of silver. this collection a paper on detonating silver, in which, after mentioning that Mr. Howard firft formed this compound, which was afterward obtained in larger quantity by Mr. Cruickshank, he points out a process for preparing it analogous to that adopted by the latter gentleman. A paper already published in this Journal † contains Former paper nearly similar results to those obtained by the professor of on the subject. Montpellier, we shall therefore confine ourselves to the differences mentioned in his observations. Mr. Figuier has seen the detonating silver explode even It explodes amid the acid solution in which it is formed, when touched more readily than is usually by a hard body. He has likewise detonated this compound supposed. when dry by simple friction with the edge of a card. These facts indicate a much greater degree of inflammability than had been supposed, and must lead us to be more cautious in preparing this substance. The professor has remarked, that detonating silver is not Not decomdecomposed by weak sulphuric acid, unless it has been pre- posed by weak viously dissolved in water. Caustic potash appeared to him merely to change its colour to a red, or a deep gray, without depriving it of its fulminating quality. This experiment, which I repeated, did not afford me precisely the same result. After remaining a considerable time in potash, the residuun gaye only a slight decrepitation, arising no doubt from the portions, on which the potash had not yet acted. * Annales de Chimie, vol LXIII, p. 104. ↑ Journal, vol. XVIII, p. 140. sulphuric acid, unless in solu tion. Nor by pure potash. Fine lake by precipitat with solution of tin. XIV. Process for making a fine Lake*. published the following process for making a beautiful lake. Take any quantity of cochineal, on which pour twice its ing cochineal weight of alcohol, and as much distilled water. Infuse for some days near a gentle fire, and then filter. To the filtered liquor add a few drops of solution of tin, and a fine red precipitate will be formed. Continue to add a little solution of tin every two hours, till the whole of the colouring matter is precipitated. Lastly, edulcorate the precipitate by washing it in a large quantity of distilled water, and then dry it. contains green fecula, XIV. On the Blue Wolfsbane, by PHILIP ANTONY STEINACHER*. Blue wolfsbane THE fresh leaves of blue wolfsbane, aconitum napellus, cultivated in a garden near Paris, being treated with a sufficient quantity of water at 45° [113° F.], green fecula was coagulated. a gas, an earthy matter, consisting of carbonate The liquor separated from this fecula retained a peculiar herbaceous smell, analogous to that of the leaves of scurvy grass after the greater part of their pungency is destroyed by exposure to the open air. The progress of evaporation entirely dissipated it. Toward the end a matter of a granular form was separated. After this was washed and dried, a portion subjected to the action of the blowpipe on platina was not melted by the interior flame, but became whitish, without swelling or decrepitating. Another portion put into weak sulphuric acid produced, and phosphate a pretty long effervescence. The evaporation of the fluid of lime, afforded acidulous crystals in the form of soft needles, which were decomposed by nitrate of lead. The precipi-. tate, heated red hot by the blowpipe on a piece of charcoal, * Sonnini's Biblothèque physico-économique, for 1808, vol. I, p. 952. ↑ Journal de Physique, vol LXVI, p. 294, ↑ was was reduced into little metallic globules, round which a slight aureola shone, accompanied with a very perceptible phosphoric smell. The extractive liquor boiled down con- and muriate of tained a great deal of ammoniacal muriate. ammonia. As other plants gathered by the side of the wolfsbane No phosphate in other plants yielded me no signs of phosphate when analysed, I con- growing near ceive the organs of this plant have the faculty of assimi- it. lating phosphorus, or its elements, and converting them into an acid. From my analysis it follows, that the aconitum napellus Summary of contains Green fecula, An odorant gaseous substance, which I suspect to be vi rulent, Muriate of ammonia, Carbonate of lime, and Phosphate of lime. its contents. Thus the existence of this phosphate in the blue wolfs- The phosphats bane, which Mr. Tutten of Wolfenbuttel announced nine- observed forteen years ago, is confirmed. meily. SCIENTIFIC NEWS. THE tion: HE annual courses of popular lectures at the Surry In- Lectures at the stitution, Blackfriars Bridge, commenced on the 31st ult., Surry Instit and will be continued every succeeding Tuesday and Thursday evening, at seven o'clock, during the season. derstand, that the following gentlemen have been engaged for the respective departments, viz. Chemistry and Mineralogy, Mr. ACCUM. Music, Mr. S. WESLEY. Experimental Philosophy, Mr. JACKSON and To Correspondents. We un I am not acquainted with any work on the subject after which E. H. inquires. The papers of Mr. Barlow aud Mr. Lyall will be inserted in our next nuinber. ERRATA. P. 167, L from bot. for Pl. V, read Pl. VI. 168, 1. 4 for complete read complex. A JOURNAL OF NATURAL PHILOSOPHY, CHEMISTRY, AND THE ARTS. DECEMBER, 1809. ARTICLE 1. On Vegetable Astringents. By JOHN BOSTOCK, M. D. Communicated by the Author. (Continued from page 222.) AMONG the constituents of galls we always find muci- Mucilage, lage enumerated, and Mr. Davy gives a process for obtain ing it in a separate state, but I confess, that I am not altogether satisfied with the force of the arguments, by which its existence is thought to be proved. Mr. Deyeux, who I believe first distinctly mentioned the existence of mucilage in galls, founded his opinion upon an erroneous supposition, that no substance except mucus is capable of pro- not the only ducing mould. The moulding, as has been shown above, evidently depends upon the other constituents of the infusion*. With respect to the tests for mucilages, the only Tests not ap one which can be considered as applying generally to them, plicable here, * As a farther proof of this position I may remark, that I have ob. served the process of moulding in Mr. Hatchett's artificial tan. VOL. XXIV. No. 109-Dɛc. 1809. R and substance that grows mouldy. |
