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metallic state with oxigenized muriatic gas; and that this gas combines with the oxigen, which the water gives up to it, to pass to the hyperoxigenized state: and these suppositions are not sufficient to explain every thing.
"In the other hypothesis, that is to say, admitting that on the former hypothesis; oxigen is capable of combining with muriatic acid, as it is with metals, and with all combustible substances, all the explanations are natural, and perfectly analogous with those given of other facts, in which oxigen is transferred from one substance to another. Only the new observations show, that, to effect the change of oxigenized muriatic gas into muriatic gas, it is necessary for the latter to be in a situation to receive the quantity of water necessary to its coustitution; which agrees with the force of its combination, which is very great in muriatic acid.
"It may not be useless to remark, that, when we Viscuss and on hypethe nature of substances, the mode of their combination, theses in geneand the changes that may take place in the elements that enter into their composition, it is easy to multiply hypothe ses: but those that are best supported by analogy, and require the fewest suppositions to connect them with the facts, so that the mind readily embraces their relation to them, should be adopted; still however not confounding their applications with the facts themselves confirmed by weight and measure, or with the inductions that immediately flow from these."
A few months ago I commenced a train of experimental New experi investigation, different from that which I have hitherto pro- ments prosecuted, which promised to be decisive with regard to these hypotheses. The results of the experiments I have performed have accordingly been such as appear to me to establish the truth of the common opinion. An account of these will, with your permission, form a communication for the succeeding number of your Journal.
Edinburgh, 17th Oct.
I am, with much respect,
Your most obedient servant,
The quotation in Mr. Murray's paper was in the original French : but for the sake of those of our readers, to whom that language is not sufficiently familiar, it is here given in English. C.
Ост. 1 W 29 76
N. B. The observations in each line of the Table apply to a period of twentyfour hours, begiuning at 9 A. M. on the day indicated in the first columu. A dash denotes, that the result is included in the next following observation.
Ninth Month, 9. Before sunset, after a serene day, cirrus clouds, pointing downward, from the W. 11. Carro, cirrocumulus, some dry haze: w.nd westerly by night, 14. Cirri and haze in the evening twilight of a bright orange coscarce seusible lour. 15. Much wind: clear. 16. a. m overcast: p. m. clear: twilight duller, with cirrostratus. 17. Much wind: very clear sky. 18. As yesterday: evening twilight luminous, orange, surmounted with rose colour, the latter somewhat in converging streaks. 19. Morning twilight obscure, with dense cirri: much dew: wind, a m. N. E. Thunder clouds at different heights, some of which moved from the S. E. There were clouds throughout the night, with lightning. 20. Wind a. m. N.E. Thunder clouds again, which grouped, and passed about 2 p.m. to the W with a few drops: nimbi, with a faint bow in the distance: evening cloudy, with two strata: wind S. E.: much lightning in the S. W. 21. a. m Cloudy. Rain, with distant 22 a m. Overthunder at one and two p. m: Nimbi and cumulostratus: faint bow. cast. Wind veered to N. W., apparently by E. Cirri, in lines from N. E. to S. W. 23. a. m. Wind fresh from S. W, with rain: p. m. fair, with various modifications 24 a m. Clear: much of cloud, which were finely coloured at sunset in the east
dew: fair day, but with clouds indicating rain: twilight milky, with a blush of red: the moon disappeared early, behind cintostratus clouds, and it rained heavily in the night. 25. Cloudy and windy, with rain. 26. a. m. Cirrus with cumulus: p. m. show
27. Windy: wet. 28. a m. Misty: p m. showers, cirrostratus, and a blush on the twilight. 29. Evening, lightning: wet night. 30. Lunar halo.
Tenth month, 1. a. m. Wind S. E. showery. 2. A little before sunrise I observed a stratus in the marshes to the S E., very nearly resembling a sheet of water; one which was seen from this vilage, in similar circumstances, about two weeks since, was actually taken by several persons for an extensive inundation. In the afternoon, large elevated cirri and cirrostrati rapidly passing at sunset from red to gray, indicated a renewal of the wet weath r. 3. Misty morning, with cirrostratus above: very wet, p. m. 4 Much wind: cloudy night. 5 Squally. 6. a. m. Cloudy, much wind: evening calm; large cirri and cirrostrati, with a blush on the twilight: a bright blue meteor in the N. W.: wet night. 7. Cloudy, with a gale of wind. 8. Fair.
Barometer: highest observation 30 19 inches; lowest 28 86 inches; range 1·33 inches. Mean of the period 29.736 inches.
Thermometer; highest observation so°; lowest 39°; range 41°.
Mean of the period 57 85°.
Evaporation 3.93 Inches. Rain 2:39 inches.
From the full moon of last period to the new moon of the present, easterly breezes with clear days, and the stratus by night. Evaporation went on increasing as the wind became stronger: dew feil in plenty, and the small meteors, called shooting stars, were abundant. The latter half of the present period brought the accustomed compensation, in rain from the westward: the approach of this was perceptible for several days before hand; and the ground being dry, it was attended at the beginning with some discharges of electricity from the clouds.
Several persons, imagining they perceived something extraordinary in the weather, have enquired, whether the present comet could bave any influence upon the seasons. It would be idle to reason upon its power without proof of its effects; and these, again, must be proved to extend, at least, over the whole northern hemisphere; for which a corner of our little island is no adequate standard. It seems within the limits of possible conjecture to say, that comets may induce some change in the atmosphere of the planets, by changing the state of the æther (if there be any such medium,) interposed between these and the sun; or by affecting the production of luminous matter on the surface of the sun itself. A comet approaching near to a planet would also disturb the atmosphere of the latter by the mere effect of its attraction: but we have a planet attendant on the Earth, which is doing this every day, and we are still unprepared duly to appreciate its power. Comets are, therefore, at present, out of the province of the meteorologist. L. HOWARD,
PLAISTOW, Tenth Mo. 16, 1811.
Experiments on the acid Phosphate of Potash: by Mr.
Crystallizable MR. Vitalis, secretary to the academy of sciences, letters,
phosphoric \ acid and pot
and arts at Rouen, and professor of chemistry in that city, having formed, in the course of his operations, a compound of phosphoric acid and potash, each extremely pure; and having obtained, by suitable evaporation, a perfectly crystallized salt; presumed that other chemists, who have all announced the uncrystallizability of phosphate of potash, were deceived.
Too modest to take on himself to contradict what had been said on this head by the ablest chemists, he sent me a small quantity of the salt, that I might examine it, and give him my opinion of it. The following are the results of my researches,
1. This salt is very white, crystallized in prisms with four equal sides, and terminated b. pyramids with four faces corresponding to the sides of the prism,
2. It has a very sour taste, and powerfully reddens in◄ fusion of litmus. It is not alterable by the air.
3. With lime-water it throws down a copious, white, floce culent, and as it were gelatinous precipitate.
4. Caustic potash evolves from it no ammonia.
5. It forms a copious precipitate with solution of muriate of platina.
6. It gives out no phosphorus by the action of heat, but it melts into a clear glass, which crystallizes and becomes opake en cooling.
7. After having been thus melted, it does not dissolve in water so easily as before.
Uncrystalliza8. A portion of this salt having been saturated with pot ble when neu- ash, and subjected to spontaneous evaporation, did not crystallize: it was reduced to a kind of viscous liquor, resem bling a solution of gum,
From these experiments it evidently follows, that the salt phate of pot in question is an acid phosphate of potash; consequently,
Ann. de Chim, vok LXXIV, April, 1810, p. 96.
that what chemists have said of the common phosphate of potash is not affected by the properties it exhibits: and that Mr. Vitalis has enriched chemistry with a new species of salt, to be placed in the class, already very numerous, of these substances.`
A Card has been transmitted to the subscribers to the Lectures at
Scientific Institution, Princes' street, Cavendish square, the Scientific announcing the commencement of the annual Lectures at that Establishment, on Tuesday the 19th of November.
The arrangement embraces the following subjects:
A popular course of twelve Lectures, on the most interesting branches of Experimental Science, by Mr. George Singer: a course on the Philosophy of the Mechanic Arts, by Mr. E. Lydiatt: and a course of twelve Lectures on Chemistry, by Mr. George Singer.
Surry Institution, Blackfriars Bridge.
The annual courses of Lectures at this Institution will Lectures on be delivered in the following order, viz,
natural philo sophy, che
1. On the Philosophy of Physics, by I, M. Good, Esq. mistry, music, F. R.S., Mem. Am. Phil. S., and F. L. S. of Philadelphia; and belles letto commence on Friday, Nov. 22, and be continued on each succeeding Friday.
2. Ou the Belles Lettres, by Edward Quin, Esq, to commence on Tuesday the 26th Nov., and be continued on each succeeding Tuesday.
3. On the Chemical Phenomena of Nature and Art, by Fred. Accum, Esq., M. R. 1. A,, F. L. S.; to commence early in 1812.
4. On Music, by W. Crotch, Mus. D., Professor of Music in the University of Oxford; to commence early in 1812.