72 PHILOSOPHICAL TRANSACTIONS. [aNNO 1786. 



The inflammability of this air has been already mentioned. It never detonates 

 with common air; nor can it be fired in a narrow-mouthed vessel, unless mixed 

 with a considerable proportion of this air. M. Scheele found it to inflame when 

 mixed with -f- of this air. According to M. Sennebier it cannot be fired by the 

 electric spark, even when mixed with any proportion of respirable air. Mr. K. 

 found a mixture of one part of hepatic air and 1.5 of common air to burn blue, 

 without flashing or detonating. During the combustion sulphur is constantly 

 deposited, and a smell of vitriolic air is perceived. A mixture of half hepatic 

 and half nitrous air burns with a bluish, green, and yellow lambent flame; sul- 

 phur is also deposited, and in proportion as this is formed, a candle dipped in this 

 air burns more weakly, and is at last extinguished. A mixture of 2 parts 

 nitrous and 1 of hepatic air partially burns, with a green flame, and a candle is 

 extinguished in the residuum, which then reddens on coming in contact with 

 atmospheric air. He made a mixture of 1 part nitrous and one part hepatic air, 

 and to this admitted 1. part also of common air; the instant the common air was 

 introduced, sulphur was precipitated, and the 3 measures occupied the space of 

 2.4 measures; this burned on the surface with a wide greenish flame, but the 

 candle was extinguished when sunk deeper. A mixture of 4 parts common air 

 and 1 part hepatic burned blue and rapidly; but a mixture of ] part dephlogis- 

 ticated and 1 part hepatic, which had stood 8 days, went oflT with a report as 

 ioud as that of a pistol, and so instantaneously that the colour of the flame 

 could scarcely be discerned. 



With respect to solubility in water, hepatic airs extracted from different mate- 

 rials difl^er considerably. In the temperature of 66°, water dissolves, by slight 

 agitation, -§- of its bulk of alkaline or calcareous hepatic air, extracted by marine 

 acid; 4- of its bulk of martial hepatic air, extracted by the same acid; -V of 

 that extracted by means of the concentrated vitriolic acid, or the dilute nitrous 

 or saccharine acids in the temperature of 6o°; -^ of sedative hepatic air; -j\ of 

 acetous hepatic air, and of that afibrded by oil of olives; and of its own bulk of 

 that produced from a mixture of sugar and sulphur. In general, I imagined 

 that which required most heat for its production to be most soluble; though in 

 some instances, particularly that of acetous hepatic air, that circumstance does 

 not take place. But the most remarkable phenomenon attending the union of 

 hepatic air with water is, that it is not permanent. Even water, out of which 

 its own air had been boiled, in a few days after saturation with hepatic air grows 



M. Fontana, is evidently erroneous ; and indeed, by that determination, common air would not be 

 even 7C0 times lighter than vi^ater, in the temperature of 55°, and the barometer 29.5, which con- 

 tradicts all barometrical and aerostatic experiments : and I cannot omit mentioning the very near 

 agreement of the weight of common air here found with that resulting from the calculation of Sir 

 George Shuckburgh, it is so great as to differ only by 2 grains in a cubic foot. — Orig. 



