glafs and try whether the contact of the air, generated from the pafte, PNEUMATICS would also communicate a colour to the liquor. Jan. 22. There was no need to perforate the leather; for I found the liquor already tinged; whence it is probable, that air produc'd from pafte is endu'd with fuch minute particles, as to penetrate leather, which is impervious to common air. Jan. 25. The liquor became almoft colourlefs; whence it appears that common air is too thick to penetrate all paffages, which are pervious to air, produc'd from pafte. Feb. 2. I put the fame vial in vacuo, but did not cement the receiver to the cover; fo that the air, gradually entring, in twenty-four hours, fill'd the receiver, as it was leifurely fill'd with the air produc❜d from pafte; yet the liquor ftill remain'd colourlefs. Feb. 15. I put the fame glass again in vacuo, with fome quantity of pafte; but this time, the air produc'd from thence, did not pervade the leather, as it had done before, and the liquor was not at all tinged. thro' water. (126.) April 2. 1678. I put a fhrew-moufe into the filtrating engine; A brew-mouse and when I perceiv'd him reduc'd to extremity, I began to ftir the pump in an engine that filtres air that the air might be, as it were, filtred thro' the water. The mouse, a while after, feem'd to be better, yet not wholly reftor'd; and having been long kept fafting, I am uncertain, whether he died for want of aliment, or of new air. April 12. I repeated the experiment with a fmall weakly moufe, that had been kept a long time without food. And finding the fame fuccefs as before, I took out the moufe before he was dead, but he recover'd not: fo that more experiments are requir'd, to fhew the effect of this filtration. (127.) May 2. 1678. Six weeks ago, I included frog-fpawn in three re- Frog-Spawn in ceivers, the firft of which was exhaufted; the fecond contain'd common vacuo, common air, and com air; and into the third, I intruded fo much air, that the mercury refted press'd air.. fixty inches above its ufual height, In fifteen days, the mercury in the evacuated receiver rose an inch. The fpawn in the common air feem'd corrupted, and of a blackish colour; but that in the comprefs'd air, remain'd unalter'd in colour; tho' no frogs were generated. In a month's time, the fperm in vacuo had not changed its colour, excepting the black round fpots; but feem'd reduc'd into water: the colour of that in the common air was very black, but in the comprefs'd air the fpawn began to be reddifh. As yet, no change was perceiv'd, either in the fpawn in vacuo, or that in the common air; but in the comprefs'd air it appear'd redder. May 22. The fperm in vacuo was not chang'd; in the comprefs'd air it remain'd red; but in the common air it again became colourless. June 23. The fperm in vacuo, and in common air was not tinged, but in the compress'd air it inclin'd to green. Octob. 15. I took the spawn from all the veffels; that kept in vacuo was almost exhaled out of its veffel, and appear'd ftagnant in the receiver, like clear water; that in the common air remain'd colourless; but that in the comprefs'd air ftill kept its red colour, (128.) PNEUMATICS (128.) May 9. 1678. Six days ago, I included two pieces of the fame Oranges in re-orange in two receivers, not quite of equal bignefs; in the greater, there ceivers, with was left fome quantity of water, fo that the fame space remain'd for the and without air in that, as in the less. The orange included with water, tho' it were not touch'd by it, was four times more mouldy, than that kept without wa water. Turpentine inluded in a wind-gun. Spirit of fal copper-filings in vacuo. ter. And therefore, in repeating this experiment, I put two pieces of the fame orange into two receivers, but fill'd the third part of one of them with water, yet fo, that it did not reach the orange. June 15. Neither of the pieces had contracted any mouldinefs. May 16. I repeated the experiment with the fame fuccess, only neither orange had acquired any mouldinefs in the space of more than a month; tho' in former experiments, all fuch oranges grew mouldy. The cause of the difference, seems to be fome particular disposition of the air. (129.) June 1. 1678. I put a small glass tube, half full of Venice turpentine, into our wind-gun; and had scarce reduc'd the air to the tenth part of its wonted space, but the leather spread over the elliptic valve, was driven out; fo that, the air having efcap'd, I drew the glafs-tube out of the engine, and found many bubbles formed in the fuperficies of the turpentine. I therefore, suspected that the air had pervaded the turpentine; and that it would have penetrated deeper into it, if they had remain'd longer thus inclos'd together. I plac'd the fame tube in the fame gun, and there left it in air reduc'd to about the fifteenth part of its natural space. June 3. I open'd the engine, and taking out the tube, found the turpentine almoft free from bubbles; yet by degrees, many were formed therein, in the parts remote from the fuperficies. June 4. I put new turpentine into the fame tube, and included it in vacuo, that it might be the better purged of air; then I pour'd the water upon it, and fhut up all in the wind-gun. June 8. I open'd the engine, and at firft fight, both the water and the turpentine in the tube, feem'd to be very free from bubbles; but foon after I perceiv'd, that bubbles were form'd in the turpentine, and that they af cended by degrees; fome of them feem'd to be made, almoft at the very bottom, about half an inch below the fuperficies of the turpentine. Whence we may conjecture, that all the water, and fo great an height of the turpentine, were pervaded by the air, which formed thofe bubbles. (130.) August 11. 1678. I included fpirit of fal armoniac, with a mercurial gage, in vacuo; and after the fpirit ceas'd to emit any bubbles, I mix'd copper-filings therewith, which caus'd many bubbles to rise again; but they were so far from producing any air, that they confum'd what was there before. But the liquor became greenish and turbid. Decemb. 5. The fpirit was almost all exhaled out of the containing veffel, and being condens'd in the receiver, remain'd ftill turbid, by reafon of much filth, which was included there: but that which was not exhaled out of the veffel, appear'd clear like water. The mercury alfo, was wholly expelled out of the gage. Whence I conjecture, that the air in the recei- PNEUMATICS ver was gradually more confumed. (131) Sept. 2. 1678. I put two cylinders, one of tin, the other of lead, Cylinders of in vacuo their loweft parts were immerfed in mercury; and at the fame tin and lead time I immerfed two other cylinders, like the former, after the fame man- immersed in ner in mercury; but these latter were left in the free air. mercury, in vacuo, and in Sept. 6. I opened the exhausted receiver, and the mercury in the tin cy- common air. linder was rifen 4 inches and a half above the fuperficies of the ftagnant mercury; and cutting the cylinder tranfverfly, in the middle of that height, the amaigam feem'd to have penetrated into the cylinder about half a line. And cutting the cylinder tranfverfly again in that part, which was diftant only one inch from the fuperficies of the ftagnant mercury, I found the thickness of the amalgam equal to one line. In the lead-cylinder, the mercury rose two inches and a half; but only as far as the fuperficies; and the very part immerfed in the mercury, was not penetrated by it to any fenfible thickness. Sept. 7. I took the tin cylinder left in the air, out of the mercury, in which it was immersed, and found the mercury to have ascended to the height of five inches. Sept. 10. The fame cylinder being left in the mercury, seemed to be befmeared therewith to the very top, fix inches and more above the fuperficies of the stagnant mercury. When the cylinder was transversly cut in feveral places, the mercury appeared to have pierced the deeper into the tin, the nearer it came to the stagnant mercury; fo that in the part adjacent to the mercury, almost the whole diameter of the cylinder, three lines broad, was penetrated thereby. In the lead cylinder, the mercury exceeded not the height of 3 inches and a half; neither had it penetrated to any fenfible thickness. Whence it appears, that the weight of the air contributes little or nothing to the afcent of mercury into metals. A (132.) Decemb. 12. 1678. I took a fmall whiting, and having cut off 4 whiting inhis head, divided him tranfverfly into five pieces; the firft whereof I in- cluded in vacluded in vacuo. The fecond in common air. The third in air fo com- cuo, in compreffed, as to fuftain mercury 50 inches above its wonted height. Thefe mon air, in air compress'd, in three receivers were clofed with fcrews. The fourth piece was put into a artificial air, receiver full of air, produced from paste, which was presently stopt. The fifth was left in the free air. Decemb. 15. In the morning, that part of the whiting which was left in the free air, began to fhine; and towards evening it gave a more vivid light. Decemb. 16. In the morning, the whiting left in the free air, ceafed to fhine; but towards evening fhone again. Decemb. 17. This morning the fame part of the whiting fhone a little, yet less than yesterday in the evening. and left in the open air. PNEUMATICS Decemb. 18. In the morning there appeared no light, tho' I long fixed my eyes upon the receiver in a dark place; but the night coming on, the light appeared again. Decemb. 20. Hitherto the fame part of the whiting left in the air continued to fhine; but all the other parts did not yet begin to do so. Decemb. 22. Yesterday, the light of the whiting, left in the air, had not quite ceafed; but this day it appeared no more. Decemb. 24. The part of the whiting in the free air, entirely gave over fhining; that included in common aif, did yesterday yield a faint light; but this day it fhone no more. Decemb. 26. No more light appeared in that in the common air; but the three other pieces did not begin to fhine. Jan. 26. 1679. I perceived no more fhining in any one of the receivers. Artificial air (133.) Aug. 3. 1677. I tranfmitted air, produc'd from cherries, into a deftroyed; and receiver full of common air, but fo ftopt with a screw, that the merfirst that of cherries tranf- cury afcended to 25 inches above its ufual height. mitted into a receiver full of common air. That of falarmoniac, and eil of vitriol, in vacuo. And of oil of vitriol with a fifth part of common air. it Aug. 4. The mercury was depreffed about two inches. The height of this day was only 23. Aug. 6. The height thereof was reduced to 20. Aug. 7. The height thereof the fame. Aug. 8. The mercury was fomewhat depreffed. Aug. 10. The height of it was 19 and a half, above its ufual ftan dard and perceiving little or no alteration,. I opened the receiver. Hence we have a confirmation, that air produced from fruits, at the beginning, is in part deftroy'd; but that the reft can very long retain the form of air. (134) May 26. 1676. I put fix grains of fal-armoniac into a receiver, with a fufficient quantity of oil of vitriol; then the air being exhaufted, I forced down the falt into the oil; whereupon a great ebullition prefently follow'd, and the mercury afcended in the gage almoft to its wonted height; but presently after it funk again, and return'd to its former state. May 27. I repeated the experiment, the falt remaining ten hours in va cuo before it was put into the oil; but the ebullition proceeded as before; yet the air was produced much more flowly, nor could it wholly be detroyed in 7 or 8 hours time; yet at laft the mercury descended to the very bottom. May 29. I made the fame experiment again, leaving the materials for 24 hours in vacuo; the ebullition feemed much lefs, and the air was produced, both in a lefs quantity, and more flowly than before. I obferved alfo, that whilft the materials remained in vacuo, before their mixture, the mercury came nearer to the open end of the gage, as if fome air had been either extracted or deftroyed. June 8. I put oil of vitriol alone into a receiver, in which I left only a fifth part of common air, to try whether this oil, without fal-armoniac, would diminish the elaftic force of the air; but the force of the air was increased, and the mercury in one hour's time feemed to have afcended a little into the gage; tho' afterwards for 24 hours no change happened. This experiment fhews, that fome artificial air may be deftroyed; but why this destruction happens, fometimes fooner, fometimes later, deferves a further enquiry. (135) July 10. 1676. I put pafte, made two days before, and now grown fourish, into a receiver, and ftopt it firmly with a screw. In one hour the height of the mercury was one inch. In feven hours the height of it was fix. July 11. The height of it was eleven. July 12. The height of the mercury was 24. July 13. The height thereof was 30. July 14. The height of the mercury was fenfibly greater. July 15. The mercury afcended a little. Measuring its height exactly, I found it 38 inches. July 19. No more air was produced from the pafte. July 10. 1676. I put another quantity of the fame pafte, much lefs Paste in vathan the former, into an exhausted receiver. Tho' the quantity of the pafte was lefs, yet in one hour's time the height of the mercury was two inches. In feven hours the mercury came almoft to the top of the gage; but it was a fhort one. July 19. The paste was not able to move the receiver from its cover; tho' at the beginning, it had produced a greater quantity of air, than the paste in common air. I endeavoured to fire it with a burning-glafs, and the fumes elevated therefrom, afterwards falling upon the pafte, tinged the fuperficies thereof with a pleasant yellow colour; and that air was thus produced, I conjectur'd, because the cover was afterwards easily severed from its receiver. Hence we learn, that air is fometimes generated much more easily in vacuo, than in common air. (136.) August 20. 1676. I put paste, kept for 24 hours, in a receiver full of common air; to which I added new air, fo that the mercury exceeded its wonted height 4 inches and a half. In 6 hours the mercury gain'd almoft 4 inches, and its height was 8. Aug. 22. The afcent of it was about I. 23. The afcent of it was half an inch. 26. For three whole days the afcent of the mercury was only half an inch. 27. There was no afcent of it at all. 29. The pafte, taken out of the receiver, fmelt acid. August 20. I put another quantity of the fame pafte into an exhausted receiver, and obferved the fame proportion between the quantity of the paste, and the capacity of the veffel, as in the former experiment. The mercury presently feemed to have afcended. Its height was two inches. Aug. cuo. |