contain common air. See Rozier's Journal for May 1775, P. 433. AS I always wish to take the earliest opportunity of publishing every new fact, and several have occurred to me fince this volume has been printed off, I fhall in his place briefly mention a few that are of fome importance. 1. Ox gall dried diffolves in the nitrous acid with as much rapidity as vegetable aftringent fubftances, and yields great plenty of nitrous air; whereas animal fubftances in general yield only phlogisticated air, with a mixture of lambently inflammable air, by the fame treatment. Now it is remarkable that the gall is fecreted from the venal blood, which, according to my theory of the ufe of the blood in respiration, is then loaded with phlogifton; while other fecretions are made from the arterial blood, which has discharged its furplus of phlogiston. 2. Ni 2. Nitrous air is presently decompofed by a folution of green vitriol in water, which, in confequence of it, becomes of a very dark colour; but becomes green. again on being expofed to the open air. In this and many other properties, the effect is the fame as that of mixing a fmall quantity of fpirit of nitre with that folution. This may lead to various useful experiments. 3. A more decifive experiment relating to the generation of fixed air than that which is mentioned, p. 353 with woodafbes, is one that I have fince made with the afbes of pit-coal. Pit-coal itself, distilled in a glass veffel, yields no fixed air, but only inflammable air, which, being fired in a wide-mouthed jar, burns with a bright lambent flame, without explofion. But the ashes of the fame pit-coal yielded much air, of which one half was fixed, and the rest inflammable. When I had expelled all the air that I could from a quantity of these afhes, I mixed spirit of nitre with them, and they immediately yielded as much air as before; and of this one half was fixed, and the reft nitrous. Mixing more spirit of nitre with the fame afhes again, the produce was the fame as before. 4. The electric fpark, or explofion, taken in common air, confined by quickfilver, in a glass tube, covers the infide of the tube with a black matter, which, when heated, appears to be pure quickfilver. This, therefore, may be the cafe with the black matter into which I fuppofed the vitriolic acid air to be converted by the fame process, p. 221. though the effect was much more remarkable in that than in common air. The explosion will often produce the diminution of the common air, in half the time that the fimple Sparks will do it, the machine giving the fame quantity of fire in the fame time. Alfo the blackness of the tube is much fooner produced by the fhocks than by the fparks. When the tube confiderably exceeds three tenths of an inch in diameter, it will sometimes become very black without there being any fenfible diminution of the quantity of air—I mention thefe few facts without any remarks, hoping that by this means I fhall propagate no dangerous errors. THE } THE Sect. III. Of the Production of DEPHLOGIS- TICATED AIR from EARTHY SUBSTANCES, made chiefly with a View to determine whether Sect. IV. An Attempt to afcertain the Quan- C 2 Sect. VI. Sect. VI. MISCELLANEOUS Experiments and Obfervations relating to DEPHLOGISTICATED AIR 85 Sect, VII. Of the Influence of the OIL of TURPENTINE and SPIRIT of WINE on Common Air 92 Sect. VIII. MISCELLANEOUS Experiments relating to COMMON AIR 100 Sect. IX. Of the Impregnation of WATER with Nitrous Air Sect. X. Of the Abforption of Nitrous Air by OILS, SPIRIT of WINE, and CAUSTIC ALKALI Sect. XI. Of the Phenomena attending the Abforption of Nitrous Air by ACID LIQUORS 121 Sect. XII. Of the Proceffes by which Nitrous Air is brought into a State in which a Candle will burn in it with an ENLARGED FLAME produced by the Solution of Metals in the Nitrous Acid 132 Sect. XIII. Of the Phenomena attending the Diminution of Nitrous Air by IRON FILINGS. and BRIMSTONE, and alfo by LIVER of SUL PHUR 4 140 Sect. XIV. |