The first day, 25th March. The flesh is become sensibly redder, and even of a more beautiful red than with nitrous gas. 2d and 3d days. The red colour has diminished, but it still looks bright. 4th and 5th days, the same. 6th and 7th days. The redness has gradually diminished; the flesh is more moist than that put into nitrous and hydrogen gases. 8th day. The meat becomes quite moist, and begins to appear livid; I can discern upon its surface some isolated drops, semi-spherical and almost transparent. 9th day. The little drops are increased in number, and gradually become opake and whitish, so that the flesh appears as if it was covered with the small-pox. 10th and 11th days. Putrefaction makes sensible progress, the flesh has become flabby, the moisture increases, and the surface dissolves; however, the little drops may still be discovered on the surface of the liquor, which covers the whole of the flesh. On the evening of the eleventh day I took out the meat, removing the recipient above the trough. It gave out a putrid garlic odour, which had some resemblance to that of phosphorated hydrogen gas. The meat continued to putrefy in the atmospheric air, just as if it had been exposed to it from the first. The volume of the oxygen gas was not diminished, it no longer inflamed a candle, nevertheless one burned in it for an instant with a little brightness. 2d. Hydrogen Gas. This was prepared by dissolving zinc in sulphuric acid diluted with water. 1st day, 25th March. The flesh took on a palish colour at the end of a few hours, afterwards it became brown, like meat that is smoked after having been salted with pickle that did not contain nitre. From the second to the eleventh day no external change was observed in the flesh; it neither became flaccid nor moist; its cohesion seemed even to increase; it appeared to be harder and drier. It lost its red colour more and more; it became more brown than meat exposed to carbonic acid. I took out the meat the evening of the eleventh day; there was not any sign of putridity, nor had it the least bad smell; at the most, one could only say it had a slight acid odour; exposed to the atmosphere it did not putrefy, but became dried; nevertheless, upon its surface might be ob served some white spots of mouldiness. The gas inflamed when the recipient was turned up and carried near a candle. 3d. Carbonic Acid Gas prepared by dissolving Chalk in Nitric Acid. 1st day, 25th March. At the end of a few hours the meat had a palish tint, it then became brown, but it continued more pale than in the hydrogen gas. From the second to the eleventh day: in the first days it appeared to become flabby and livid, then no further change could be observed. I could not see that the surface became moist. The carbonic acid gas employed for the experiment was absorbed by the water; more readily it appeared than when it was purer, for I was obliged daily to add more gas to prevent the water touching the meat. The evening of the eleventh day I took out the meat, which had not the least sign of putridity; it resembled cooked meat, it was flexible, but neither inoist nor sticky: it had a slight acidulous odour, something like sour yeast; exposed to the atmosphere it did not putrefy, but dried, and its surface was covered with small white spots. 4. Nitrous Gas obtained from Copper and Nitric Acid over Water. 1st day, March 25. The meat became of a more beautiful red than in the atmospheric air, and could not be distinguished from that in the oxygen gas for several hours. 2d and 3d days. There was not any alteration. 4th, 5th, and 6th days, the red colour was a little diminished, but it was still very bright. 7th to the 11th day I could not perceive any change, except that the meat became a little moist, but it was not dissolved upon its surface. Its cohesion even appeared to be increased. On the evening of the eleventh day I took out the meat; it was of a fine red colour, firm, and had not the least smell, not even of nitrous gas. Exposed to the air, it lost its red colour in a few hours, became brown, and dried up more speedily than the meat in the two former experiments. Its surface was not covered with white spots. The gas tried with oxygen gas gave out red vapours, and was greatly diminished in its volume. It did not sensibly differ from common nitrous gas. Second Set of Experiments from the 5th of April to the 10th of June. The temperature of the external air was on the morning of of the 18th of April, 2° 5, and on the 17th of May, at noon, 23° 3. The temperature of the room was between 7° and 20° (Reaumur.) The meat employed for these experiments was paler than the former, and appeared to have been taken from a younger ox. Oxygen obtained from red Oxide of Mercury. The Experiment made over Mercury. 1st day, April 5. The meat had become much redder; 2d and 3d days, no sensible change; 4th and 5th days, the meat was of a paler colour; 6th to 8th day, the colour was quite destroyed, and the meat looked as if it had been washed. 9th day. Small drops appeared upon its surface, as in the first experiment. 18th day. The drops are become opake, and resemble pustules of the small-pox. The meat preserves its consistence without dissolving, although the temperature was higher than in the last experiment. 19th to the 51st day (25th of May). I could observe very evident signs of putrefaction at the surface, the globules had united, and the surface was become black. An accident having occasioned the overthrow of the vessel, the gas escaped, and filled the whole house with such an offensive odour, that I was obliged to make use of the strongest perfumes to overcome it. Oxygen obtained from Nitrate of Potass. Experiment made in an empty Vessel, close stopped with a Cork Stopper. 1st day to the 3d. The meat did not become more red. 4th day it was paler. 5th day to 51st. I could not observe any globules, the meat gradually grew paler, putrefied, and dissolved at the surface. At last a considerable quantity of fluid was formed, of a bad colour, which ran into the neck of the bottle. The meat was covered with moisture; the odour was less strong than that from the meat putrefied in the oxygen gas, and of a different kind. Atmospheric Air. Experiment made over Mercury. 1st and 2d days, (5th and 6th of April). No remarkable change. 4th day. The meat had become very pale, much paler than in the oxygen gas. 5th to 51st day. No drops of liquor could be perceived. From the 8th day the meat was moist and dissolved on the surface, but less so than in the oxygen gas; and at the end of the experiment it was not so black as that in the pure oxygen gas. When it was taken out of the recipient, it did not smell so strong, and its colour was much redder when cut into. Pure Hydrogen Gas obtained from the Vapours of Water, passed over red-hot Iron. Over Mercury. 1st day, (April 5). The meat became of a crimson red. 2d to the 51st day. No other change could be observed than that the meat became a little brown, but it had not a livid colour. It is remarkable that this meat preserved its red colour and retained an appearance of freshness, while the pieces put into the oxygen gas and atmospheric air grew pale. When it was taken out of the receiver, it had not the least smell. The gas at the end of the experiment rendered lime water turbid. Pure Hydrogen Gas, in a Bottle with a Cork Stopper. From the 1st to the 51st day the meat was not in the least brown, it preserved its colour, and only appeared a little moist. When taken out on the 51st day it had not the least bad odour; its smell something resembled that of smoked meat. The gas tried by nitrous air was not sensibly diminished, it rendered lime-water slightly turbid, and afterwards burned with great vivacity. [To be continued.] XVI. On Heating Buildings by Steam. To Mr. Tilloch. DEAR SIR, HAVING frequently troubled you on the subject of heating buildings by steam, I beg leave to mention that considerable progress has been made in it since the publication of my Essay on Fuel, and since I last wrote to you. A place of worship has been for a considerable time heated by steam on a most simple plan, so as to require little or no attendance, and does not require any water whatever to be added to that first put into the boiler above thrice in a winter. This is an important fact, and so is the following. I have seen another mode, by which a fire of three hours in the morning serves for heating the whole of the rest of the day. This does away the objection to the use of steam. as formerly applied for many purposes, such as hot-houses, &c. and is an introduction of a new principle, if I may use the expression, from which important practical benefits may arise. I am your most obedient, ROBERTSON BUCHANAN, XVII. Proceedings of Learned Societies. ROYAL SOCIETY. June 27. THE President in the chair. Professor Playfair furnished a lithological survey of Shehalean, one of the Grampian mountains in the north of Scotland, on which the late Dr. Maskelyne made his ingenious experiments to ascertain the attraction of the mountain on a plummet, and also the mean density of the earth. Part of this paper consisted of mathematical tables of a nature not to be read. The professor discovered with some difficulty the partswhere Dr. M. had taken his angles from, and then proceeded to examine the rocks which compose the mountain: these he found to be chiefly granular quartz and micaceous schist, with their varieties. Mr. P., after taking a general survey of the position, bearings, surface, elevation and perpendicular sides of the mountain, collected specimens of the different rocks which compose it, and ascertained their specific gravity with great care and minuteness. July 4.-A paper by Dr.Wells was read on vision. The purport of the author's observations was, that the focal distance of the eye depends chiefly on the contractibility of its muscles, and that the latter is much greater in youth than in persons of more advanced years. In youth the eye is capable of accommodating itself to the light and the distance of external objects, but in old age this contractile power of the muscles ceases, and the focal distance of the eye becomes shorter, and more fixed to a determinate point. Dr. Wells has made some experiments both when young and old, and caused others to make similar ones, with bella donna applied to the eyes: this plant increased the action of the ocular muscles in the young, but not in the old subject. Hence he inferred that short sight is less owing to the prominence or figure of the pupil, than to the flexibility of the muscles which direct it. The Society then adjourned, during the long vacation, till Thursday the 10th of November next. XVIII. Intelligence and Miscellaneous Articles. THE eleventh Number of Leybourn's Mathematical Re Pository contains, 1. Solutions to the mathematical questions proposed in Number IX; 2. Solutions to a curious problem in dynamics; 3. Expansion of a formula con nected |