VOL. XIII.] PHILOSOPHICAL TRANSACTIONS. 653 



experiment ought to be made in an open vessel, where the air has free access. 

 This succeeded with oil of petroleum, and de lateribus : but sallad oil and spirit 

 of wine could not be made to flame. 



The ingredients that compose this burning mixture, are apart cold to the 

 touch, and some of them in their operations : thus, water and oil of vitriol are 

 cooling in their nature; but these in conjunction cause a great heat, which soon 

 excite the agile particles of the phosphorus to an actual fire; and this meeting 

 with an inflammable ingredient, such as oil of turpentine, or the like, produces 

 as considerable a flame as boiling oil is wont to do. 



ExPT. IV. Being a Refutation of Borrichius's Experiment that pretends to 



Accension, 



We took, according to direction, 4 oz. of fresh drawn spirit of Venice tur- 

 pentine, to 6 oz. of aquafortis, newly drawn and very strong. We mixed 

 them together in a glass vessel, and placed it in the sun beams. After half an 

 hour's patience, the liquors began to ferment furiously, insomuch that a very 

 great smoke was raised by this means, which was directed to be kept down by 

 a cork that stopped the vessel. This condensed red fume represented flame, 

 by reason of the beams of the sun, that were permitted to shine upon it : but 

 I was assured that this was a great fallacy. I was willing to give the experiment 

 every advantage, which made me perform it where the beams of the sun were 

 admitted ; but this very circumstance giving ground to the mistake, I desired 

 leave to make the experiment in a dark room, where we should better discern 

 any real productions of light ; being assured, that the action of the liquors 

 would as certainly succeed in the darkened room as in a light one. The expe- 

 riment was repeated, and the action of the liquors was no less vigorous than in 

 the former instance. And flax, being considered as a very combustible matter, 

 was suspended in the fume: but none of the persons present could discover 

 the least spark of fire or glimpse of light; so that the flax remained untouched, 

 and the fermenting liquors gave no light, fire, or flame. Only take this cau- 

 tion ; keep your candles at a distance, for the fume will soon take fire at any 

 actual flame, and set the liquors a burning, and so it may impose upon 

 the careless.* 



* Borrichius's assertion respecting the inflammation of oil of tiupentine by aquafortis, (nitrous 

 acid) is not disproved by this failure. Supposing Dr. Slare to have employed a well rectified oil of 

 turpentine, and a concentrated, smoking nitrous acid j yet his manner of mixing the oU and acid 

 together might not have been proper. It is not stated that the acid was poured upon the oil at dif- 

 ferent intervals, and not all at oncej though this circumstance is requisite to the success of the ex- 

 periment. Certain it is that oil of turpentine, like other essential oils, may readily be inflamed by 



