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blue in one di&illation, and continued fo for 18 
months, till I made ufe of it. 
_ -A great quantity of air was fet free from the be- 
ginning to the end of the diftillation, owing in a 
great mealure to the acid fumes aiding on the iron 
Dody ; for it diddled in a glafs or (lone vetlel, the 
quantity of air is not near fo confiderable. 
The nitrous fumes condenfed in water, in mak- 
ing the ipiritus nitri fortis appear to be more acid 
than the dronged oil of vitriol made ufe of for the 
experiments on fpirit of fait. 
Water is not heated by thefe fumes, owing pro- 
bably to the fmalleft of the quantity which con- 
denfes therein. 
A further application of this new method of Di- 
fl illation . 
In the diddlation of the oil of vitriol, a great part 
of the acid comes over fulphureous, and is very hard 
to condenfe ; but, by pafling it through water, this 
condenfation is eafily obtained : however, a greater 
quantity of water is neceffary for this operation 
than for the fpirit of fait, though the water be- 
comes but flightly acid, yet it is greatly fulphu- 
reous, and at the fame time acquires no heat. 
The fulphureous acid obtained by other means, 
as by diddling the acid of vitriol with mercury, 
and other fubdances, is likewife condenfible. 
Further, this fulphureous acid of vitriol may, by 
two or three flow rectifications, be deprived of its 
acid j but it will dill retain its penetrating fulphu- 
reous gas-like fmell. 
The 
