• fV

26 Observations on

though the heat had been so small as to haveproduced no change of colour in the acid.was so much phlogisticated, that one mea-sure of it, and one of nitrous air occupiedthe space of 1.81 measures,

SECTION II.

Of the Nitrous Acid Vipour.

I N the third volume of Observations onAir, I observed the remarkable effectsof impregnating oil of vitriol with nitrousacid vapour. It was one of the last obser-vations that I made before the printing ofthat volume.

Having impregnated a larger quantity ofthe oil of vitriol than I made use of inthose experiments, I left some of it in alarge phial, with a ground stopper, amongother phials containing things for which Ihad no immediate use. But though myprocess was over, that of nature was not.Happening to be looking at it on the 19thof March following, perhaps about fix

months.

i