diftilled liquor, which I exposed to the action of various acids, and a violent effervefcence enfued: I then poured fome of the fame liquor upon fyrup of violets, and it produced as fine a green as fpirit of hartshorn; this tincture having been changed to a red, by the affufion of a few drops of aqua-fortis, became again blue, upon pouring into it fome more of the distilled liquor. The liquor that distilled the five following days, gave the fame indications of an alkali. As the diftillation entirely ceafed after this time, I broke the alembic, and found juft fuch a refiduum as before, but under it there was a small portion of liquor, reduced to the confiftence of fyrup, which retained fomewhat of an alkaline quality, but fo weak, that having expofed it about twelve hours in a window where the heat of the air was equal to about ten degrees of Reaumur's scale, the alkali totally difappeared. 13. This effervefcence, and power of changing fyrup of violets green, proves that putrefcent humours form a true alkali, which exhales with a very flight heat. I would have made the experiment upon the fyrup of violets with the putrid humours themselves, but the opacity of the ferum, the red colour of the blood, and the yellownefs of the bile, would have rendered it doubtful. 14. As the refiduum left in the alembic after diftillation, though not alkalefcent, is extremely fetid, it is evident that though the alkali may difengage and exalt this fetor, and render it more penetrating, it is not the productive cause of it, because the fetor remains when the alkali is departed. 15. But as both the alkalescence and fetor disappear in the fame degree of heat, if long continued (Par. 5.) it appears that this fetor is produced by the effluvia of parts extremely volatile, but different from volatile alkali, which, though fooner produced, are more flowly diffipated, fince the fetor generally continues longer than the alkalefcence. Alkalescence may, however, be fometimes connected with a flight fetor; and, on the contrary, extreme fetor may fubfift without alkalefcence. This is a confirmation of the difference between the fetid and alkaline particles, which the ingenious Dr. Pringle has demonftrated by another argument; he obferves, that the exhalations of fresh urine are not pernicious, though they contain more alkali than any fubftance in a state of putrefaction, the odour of which is pernicious in the highest degree. Putrid effluvia, therefore, are of a different nature from alkaline falt. 16. This being the fact, it follows that a volatile alkali is not a neceffary product of putrefaction, and that the degree of alkalefcence is not equal to that of putrefaction; but that, with refpect to vegetable fubftances, neutral falts, if mixed with oil, become volatile by means of putrefcence, though in animal bodies alkali commences by the action of the bowels, where enveloped with other principles, it becomes perfect, or manifefts itself by putrefaction; and that for this reason, putrefaction engenders a quantity of alkali more confiderable in proportion as it finds in putrefcent bodies more falts, and other elements, capable, by mixing with falts, of communicating to them an alkalefcent volatility. Upon the the whole, if it is confidered, 1ft, That acefcent plants, plants that yield an acid in diftillation, yield very little of it when they are converted into blood or humours by the actions' of the folids in an animal body; that they putrify almoft immediately, and yield in diftillation, instead of an acid, an alkali in a great quantity; 2dly, That an alkali is fooner brought off by diftillation from putrified fubftances than others. 3dly, That almost all falts are destroyed by the action of the bowels, and putrefcence, and that no alkali is found in the afhes of bodies confumed by fire; and, 4thly, That the humours which abound with falts, particularly the urine, afford the greatest quantity of alkali, after putrefaction; I fhall be juftified in adopting the opinion of the chymifts, who fuppose that volatile falts owe their origin to other falts, which are thus changed, by the action of the bowels in animal bodies, by putrefaction, and by fire, and that, totally lofing their original form, they become alkalies. Upon this fuppofition it will be easy to conceive how volatile falts refift putrefaction, as well as falts of other kinds, although putrefaction produces them. The quantity of alkaline falts produced by putrefaction, is indeed in proportion to the quantity of natural falts pre-existing in the putrefying fubftances; but as thefe falts are not fufficient to prevent putrefaction, it is not furprising that the alkali which refults, cannot arreft its progrefs. If the natural falts had been Atill more abundant, there is reafon to think that they might have retarded its effects; for urine, which contains the greatest quantity of falts, is leaft fubject to putrefaction; and when it is become putrid, its effluvia is lefs hurtful than the effluvia of any other humour, which can be attributed only to the abundance of the pre-exifting falts, and the ftrength of the alkali that is formed out of them. 17. The urine of a perfon in health will not become putrid in lefs than three days, fo as to effervefce with acids; but the urine of a perfon fick of a putrid fever, will become fo putrid as to produce that effect in four and twenty hours. The blood of a perfon fo diseased will also fhew figns of alkalescence much fooner than the blood of a perfon in a pleurify. Thefe particulars, however, belong to another clafs of experiments, which I referve till a future opportunity, and in which, after an examination of the morbific humours, and a comparifon of the phenomena which they exhibit, with each other, I fhall endeavour to deduce fuch confequences as may facilitate the difcovery of the causes of diseases, explain their natures, and direct the method of cure. Experiment on the beat that may be caufed by the rays of the fun reflected from the moon. By M. De la Hire, the fon. From the Memoirs of the Royal Academy of Sciences at Paris. I T is well known, that a great number of perfons attribute to the moon feveral qualities, without producing reafons founded on good experiments. I fhall not enter into a detail of thofe qualities, having remarked, that most of those I 2 who who attributed them to the moon were of different fentiments. The quality, it feems, which might be. attributed to her with moft reafon, is heat because her light is that of the fun reflected, which fhould caufe heat, as all know.. Yet as no experiment, that I know of, has been made to invalidate, or fupport, the reafons one might have to attribute this quality to her, I made the following, as exactly as I could, to know what thould be believed herein. In the month of October laft, the moon being in the day of her oppofition, and the fky very ferene, I expofed the burning mirror of thirty-five inches diameter, which is kept in the obfervatory, and towards the focus I laid the bowl of an air-thermometer of Mr. Amanton's, which is the moft fenfible we have; fo that the bowl, which is of two inches diameter, received exactly, throughout its whole furface, all the rays that affembled in the focus; having examined the height of the mercury in the tube, after leaving it there for fome time, I did not find it different from what it was before, though the rays were affembled in a space 306 times lefs than their natural ftate, and confequently, should have aug mented the apparent heat of the moon 306 times. It feems that if fuch an experiment as this (wherein not only are affembled the rays of the moon in a fpace 306 times less than their natural ftate, but wherein alfo they are obliged to cross each other as they affemble, which increases the effect of thofe united rays, as is evident by expofing the mirror to the fun) fhews no apparent heat, we fhould believe, that it cannot make any impreffion of fenfible heat in our bodies. On a fingular bone, found in the lower belly. From the history of the Royal Academy of Sciences at Paris, for the year 1760. A Bavarian foldier, who died at the age of 51, in the Military Hofpital at Bruffels, and who had ferved z8, enjoyed a good state of health till he was 50 years old; at that age he began to complain of a hardnefs in the belly, and to be fubject from time to time to a retention of urine, which he could cafe himself from by turning on the right fide, and inclining a little on his belly. None knew what this ailment could be attributed to; but, having been opened after his death, occafioned by an inflammatory difeafe, it afforded no finall aftonishment to difcover what had been the caufe of it. In the pelvis was found a kind of bone weighing 20 ounces, which was lodged towards the right fide, between the bladder and the os pubis. only connected with the mefentery, and had no adhesion with the neighbouring parts: it was inclofed by a very thin membrane fastened to the mefentery by a thick and glandular body, having the form of a cone; the point of this cone was inferted in a cavity at the upper part of the bone having drawn upwards this faftening which was more membranous than cartilaginous, the bone followed without requiring to cut any thing, or even to make any effort: By the weight and pofition of the bone it appears, why the foldier cafed himself of his retention of urine by placing It was himfelf himfelf on his right fide, and inclining a little forward. A remarkable particular in this bone was, that it was marbled, and more heavy and hard than bones ufually are. It would have been perhaps difficult to guess, that it was fuch a caufe that produced the fenfation of hardness which this foldier had in his belly, and the retention of usine to which he was fubject; and it would have been not lefs diffi. cult to explain how this bone could have been formed; but it is always of great importance to collect facts of this kind; they exhibit to us the deviations of nature, and may serve skilful men for knowing a like cafe, and perhaps delivering the patient of his ailment, in ridding him, by a bold operation, of this foreign body. The academy had this obfervation from M. Terence Brady, phyfician to his royal highnefs prince Charles of Lorrain, who fent with it a drawing of the bone, wherein is feen the manner of its being marbled, which is fomething very fingular. It were to be wished that this able phyfician had made a more accurate examination of this bony mafs, in order to fee whether its fubftance was really of the fame nature with that of bones; for there are fubftantial reasons to doubt it is. The trance of a valt cavern, a body of real ftone, of an irregular figure, but quite porous, which he had the curiofity to open. He was very much furprised to fee the whole divided into oval cells of three lines in breadth, and four lines in length, placed all manner of ways about each other, but no where communicating, all of them lined with a very thin membrane, and what was more wonderful, each inclofing a maggot, or a fly perfectly like a bee. maggots were very hard and very folid, and might pafs for petrified; but the lies were only dried up, and well preferved as antient mummies; and small-oval grains, which appeared to be eggs, were often found under them. There was at the bottom of many of the cells a thick juice, blackish, very hard, appearing red when expofed to the light, very fweet,. making the faliva yellow, and inflammable as refin. It was, in short, real honey; but who fhould ever think of finding honey in the bofom of a stone ? M. Lippi conceives that this was a natural hive, which at first had been formed in a loose, light, and fandy earth, and afterwards was petrified by fome particular accident. The animals that inhabited it were furprifed by the petrification, and, as it were, fixed in the fate they were then found. Their dried up mucofity had formed the membrane that lined the cells. At the time when the hive was yet foft, the bees went out of it to feek their food, and make their honey in it. Still feeking in the fame place other particulars to clear up this fact, M. Lippi found, in feveral I 3 parts, parts, the beginnings of a like hive. It was, as it were, the first bed, formed of a number of little cells for the moft part open, and containing the animal in all its different ftates, but dried up and very hard as well as the hives. He faw befides on one of the first beds a fecond compofed of a heap of little hillocks of about five lines in height, and an inch diameter at their bafe. They were grumelous, easily reducible into duft, and nearly refemble the hills thrown up by moles. M. Lippi opened them by ftriking gently against them, and found in every one of them two or three oval cells, filled with a yellow maggot, and full of juice, which occupied them intirely. It is easy to conceive that on a firft bed once formed feveral others are also formed, which conftitute the whole hive. But how are these beds formed? Whence comes the earth they are conftructed of? Does the animal carry it thither; and how does he carry it, and in fo great a quantity? This is not yet known; time alone can make us acquainted with this branch of knowledge. An extract from Ambrofe Beurer's Differtation on the Ofteocolla. which the author fubjoins ten German names.] The ancients were unacquainted with the nature of this ftone; fome fuppofing it to be petrified bones, others a fpecies of gypfum or plafter. The ofteocolla grows in the dutchy of Croffen, in Silefia, Pomerania, Heffe, Saxony, Poland, at Darmstadt, Heidelberg, Spire, Pena in Mecklenburgh, in the marquifite of Bradenburg, near Befkau, Sonneberg, and Droffen, The foil in which it grows is always fandy and barren, and the only trees under which it is found are poplars. Kreuterman met with one reprefenting the figure of a house or caftle, but it seems rather to have been a tophus than an ofteocolla. And Mercatus was certainly mis taken, when he gave that name to petrefactions and calcareous tophufes, Hermanus pronouncing thefe laft, to be rather bolaria or cifti. As to its production, it grows, as has been faid, in fandy ground, fomé feet deep, and has the figure of a root. The largest can hardly be grafped with both hands, but they vary in fize, like other roots. The ofteocolla, while it remains under ground, is always foft like clay, and when rubbed HE ftone ofteocolla has fe- with the hand, grows quite talTHE Tveral names given it, but lowish; but, when expofed to the the most common is ofteocolla, from the Greek word orov, bone, and Kóλ, glue; it is alfo called lapis oftites, ollofteos, offina, offifana, offifraga, lapis Afiaticus, pierre de monti, lapis Morochius, flores arenæ, foffile arborefcens, lapis fabilis, lapis arenofus, [to air, it hardens like chalk, and affumes the fame colour. In its original ftate it appears like a mixture of grey, yellow, and white clay, and fand flicks plentifully to its outfide; and it is with infinite labour and care that it can be taken up entire; for at first, a fmall |