the Nitrous Acid.

2 5

the glass with a blow pipe it was stronglypressed inwards, so that there seemed tohave been little or no communication be-tween the air within and that without.When that crack was made I cannot tell;and I must leave it to the opinion of myreader, whether it be probable, all cir-cumstances considered, that the acid had,in any measure, escaped by that crack.

I have observed, in my former publica-tions, that common air is phlogisticatedby continuing a considerable time involvedin the red vapour of spirit of nitre. This,contrary to my expectation, I also found tobe the case with the colourless, or invisiblevapour of spirit of nitre, after all the colour-ing phlogistic matter had been driven outof it. Air that had continued only twodays in a phial with a glass stopper, whichcontained some of this colourless acid, wassensibly less affected by nitrous air thancommon air was; and the air that had beenconfined in the same glass tube in whichsome of the colourless nitrous acid had beenplaced in the sand furnace only two days,

though