40 ESSAY IV. 



SECTION III. 



Among Mr. Scheele's experiments, I was particularly 

 struck by one in which he obtained no earthy crust on 

 distilling fluor with vitriolic acid, when he had put spirit 

 of wine into the receiver. I repeated this experiment, in 

 hopes that, by putting but little spirit into the receiver, 

 I might procure a new kind of ether. 



With this view, I put 1 oz. of finely powdered fluor, 

 that had been before heated red hot, into a glass retort, 

 and added 3 oz. of white English oil of vitriol ; the receiver 

 contained 3 oz. of highly rectified French brandy. 



I had continued the distillation for three hours in a 

 gentle heat, when the acid, having made its way through 

 the bottom of the retort, put a stop to the process, part 

 of the mixture running into the sand. 



On the surface of the spirit I could not observe the 

 least trace of any crust ; but in the place where the receiver 

 had been in contact with it, there was a thin ring of 

 transparent jelly. 



The same mixture of fluor and oil of vitriol was again 

 put into a retort of very strong glass, and the same spirit, 

 as in the former experiment, set in the receiver. The dis- 

 tillation was continued in a sand-bath for two hours, at 

 first with a gentle, but afterwards with a stronger heat. 

 When the distillation was half over, the spirit of wine 

 began to change into a thin jelly ; and at the end of the 

 process I found some firmer pieces at the bottom. These I 

 washed with some spirit of wine ; and, in order to obtain 

 the spirit, together with the acid, in a pure state, I poured 

 it into a large retort ; as the retort grew warm, the opal- 

 coloured spirit grew clear and swelled; what passed over 



