Professor Green on a case of sudden Crystalization. 93 
culty, and we let in both gases at once, or the hydrogen 
only, and the oxigen as it is wanted, and thus produce as 
much water as we choose, or as our gases will afford. 
The experiment may be performed without first filling 
_ the bottle with oxigen gas, and by operating with it full of 
common air, but the nitrogen, ina degree, obstructs the 
combustion, and the result is less satisfactory. 
This little application of Mr. ant s blowpipe may, per- 
aps; be of some use to chemical. demonstrations, and 
serves to evince the additional vitae of this fine instrument. 
For an illustration of the above description, see the draw- 
ing ona plate, at the end of this Number, where a section 
of the pneumatic cistern, with the -air ee. recurved 
tubes coming from them and terminating in the blowpi 5 
and the connexion of the latter ee abe “bet, ar re ex- 
hibite d. ae eae 
F) 
nen ao ee 
Art. XIV.—On an instance of instantaneous Anais 
’ Hone Professor Coxe of Princeto 
THE instantaneous erystalzation of a fees 50 lution 
of the sulphate aor com! s salt, is fa- 
miliar to. every « one ‘ihe. makes metho i and 
perhaps the crystaline process I shall now mention, has been 
often noticed before—I send you, however, the following 
oe as I have not seen it any of the books on Chem- 
vie preparing the nitrie acid from nitrate of potash and 
sulphuric acid, I had occasion to stop the process — just as 
the red fumes of the nitrous gas made their 2 a 1€e, 
id of | ones: when a bE spitadwes letely 
colitis werfoetly re itt and ie dining the. at 
mospheric air no change took place, b but upon. . 
it a small piece of the nitrate of see) érysinination: im- 
mediately ensued, and the whole was quickly solidified. 
There was, I think, a Beer _ of calons extricated 
during the above process, than in the instantaneot li- 
zation of the sulphate of aide: another? ieronce was, 
that the solidification did not, as far as I observed, com- 
