relative to Black, Watt, and Cavendish. 127 



In a subsequent part of the same treatise, Boyle adds an 

 account of another discovery of a similar kind. " I took," he 

 says (exp. 42), " whole pieces of red coral, and cast them into 

 as much spirit of vinegar as sufficed to swim about an inch 

 over them : these substances I made use of that the ebullition 

 upon the solution might not be too great, and that the opera- 

 tion might last the longer." It gave but few bubbles, till the 

 receiver under which it was placed was exhausted ; " then the 

 menstruum appeared to boil in the glass like a seething-pot. 

 To avoid suspicion, that these proceeded not from the action 

 of the menstruum upon the coral, but from the sudden emer- 

 sion of those many little parcels of air that are wont to be 

 dispersed in liquors, we conveyed over distilled vinegar alone 

 into the receiver^ and kept it awhile there to free it from the 

 bubbles, which were but very small, before ever we put the 

 coral into it. The former experiment was another time tried 

 in another small receiver with coral grossly powdered, and the 

 success was much alike." 



Of the two gases thus first obtained and separated, he ob- 

 served some time afterwards that the one was inflammable*, 



* " Having provided a saline spirit, which by the uncommon way of pre" 

 paration was made exceeding sharp and piercing, we put into a phial, ca~ 

 pable of containing three or four ounces of water, a convenient quantity of 

 filings of steel, which were not such as are commonly sold in shops to che- 

 mists and apothecaries, those being usually not free enough from rust, but 

 such as I had awhile before caused to be purposely filed off from a piece of 

 good steel. This metalline powder being moistened in the phial with a 

 little of the menstruum, was afterwards drenched with more, whereupon 

 the mixture grew very hot, and belched up copious and very stinking fumes, 

 which, whether they consisted altogether of the volatile sulphur of the 

 Mars, or of metalline steams participating of a sulphureous nature, and 

 joined with the saline exhalations of the menstruum, is not necessary here 

 to be discussed. But whencesoever this stinking smoke proceeded, so in- 

 flammable it was, that upon the approach of a lighted candle to it, it would 

 readily enough take fire, and burn with a bluish and somewhat greenish 

 flame at the mouth of the phial for a good while together; and that though 

 with little light, yet with more strength than one would easily suspect. 

 This flaming phial therefore was conveyed to a receiver, which he who ma- 

 naged the pump affirmed that about six exsuctions would exhaust. And 

 the receiver being well cemented on, upon the first suck the flame suddenly 

 appeared four or five times as great as before, which 1 ascribed to this, that 

 upon withdrawing of the air, and consequently the weakening of its pres- 

 sure, great store of bubbles were produced in the menstruum, which break- 

 ing, could not but supply the neck of the phial with store of inflammable 

 steams, which as we thought took not fire without some noise. Upon the 

 second exsuction of the air, the flame blazed out as before, and so it like- 

 wise did upon the third exsuction ; but after that it went out, nor could 

 we rekindle any fire by hastily removing the receiver: only we found that 

 there remained such a disposition in the smoke to inflammability, that 

 holding a lighted candle to it a flame was quickly rekindled." — New Ex- 

 periments touching the Relation between Flame and Air, 1671. 



