720 PHILOSOPHICAL TRANSACTIONS. [aNNO ITQO. 



air, and anim si hepatic air. It seemed extremely probable, that theses aerial 

 fluids, slowly combining together," formed the oily empyreumatic substance 

 which was collected at the bottom of the jar, while the air was undergoing the 

 diminution described above. l"'his conclusion was confirmed by trials that were 

 made with the empyreumatic oil that came over during the latter part of the 

 distillation : for when it was examined by chemical tests, soon after it was ob- 

 tained, it was found to contain fixed air, volatile alkali, and animal hepatic air. 



Dr. C. next endeavoured to determine the products which result from the 

 combustion of pure air, with animal air, or with the compound aerial fluid ex- 

 tricated from the lean of animal substances by heat. With this intention he 

 exposed the lean of fresh mutton, in a small coated glass retort, to a red heat. 

 The air which was received over mercury towards the end of the distillation, was 

 divided into 2 separate portions ; one of which was agitated with water till the 

 soluble part was absorbed ; the other was not agitated with that fluid. One mea- 

 sure of the former was introduced, over mercury, into a strong glass tube 

 adapted for the purpose of firing aerial fluids by the electric shock. This was 

 mixed with one measure and a half of pure air. The portion of the tube occu- 

 pied by the mixture was 1-j^ inch. A small shock being made to pass through 

 it, a violent explosion took place, and the space occupied by the residue was -^ 

 of an inch. The height of the mercury in the tube, before the combustion, 

 was 4.8 inches. After the airs were fired, its height was 5.1 inches. Allow- 

 ance being made for the difference of expansion produced by this cause, it 

 appeared that the volumes of the airs, before the combustion, and after 

 it, were as 100 to 75 nearly. The residue being agitated with water, 

 -j% were absorbed ; and the portion which was thus absorbed was found, by the 

 precipitation it produced in lime-water, to be fixed air. Of the insoluble re- 

 mainder, 5 parts being mixed with 5 of nitrous air, a diminution of 3 parts 

 took place ; whence it follows, that -l of the insoluble residue was pure air. The 

 pure air used in this experiment had been previously agitated with water, to free 

 it entirely from fixed air, and the inflammable air had undergone a similar agita- 

 tion. It is therefore manifest that, by the combustion of the pure and inflam- 

 mable air in the foregoing trial, fixed air was produced ; the phlogisticated air, 

 found in the residue, being that which was contained in the pure air before the 

 inflammation took place. 



Dr. C. next examined the products resulting from the combustion of pure air 

 with that portion of the animal air which had not been previously agitated with 

 water. One measure of this fluid, at the expiration of 3 quarters of an hour 

 after it had been obtained, was mixed over mercury with one measure and a half 

 of pure air, and fired by the electric shock. The portion of the tube occupied 

 by the mixture, before the deflagration, was 1 inch and -jVo *» ^^er the deflagra- 



