C 469 ) 
afterwards being defirous by a further Tryal a doubt I 
had, I kept the Glafsyet longer in the fame place with the fame 
Filings and ^en^rmm in it for (if I mif-remember not) amonech 
or two together ; but obferved not,that the liquor w^ould any more 
grow clear. 
Eocperiment th$ Sec0nd. 
Having taken fuch aGJafs,as is mentioned in Experiment the fir fl^ 
wherein the liquor was grown clearer than is ufual, and had pro- 
bably been fo a good while before, (for the Veffel, having been hid 
by others which flood before it, had been for fome weeks forgot- 
ten,) We took out the ftoppleand left it open for about half an 
hour,but did not perceive the liquor t0 have acquired any colour 
fo ranch as at the top. Whether this proceeded from the long de- 
barring of commerce with the frefh Air, or from foine other caufe^ 
being unable to wait the event as long as would perhaps be requi« 
fite, I thought fit to try, Whether the Air had already had fome 0» 
peration upon the liquor, though it did not yet appear; and ac- 
cordingly putting in the ftopple, I left the Veffel clofed for two 
or three hours, and at my return to vifit it, I perceived,that it had 
acquired a faint colour tending to a green \ wherefore taking out 
the ftopple again, lopen'd its Commerce with the outward Air , 
leaving theGlafs unftoptfor 20 or 24 hours, but found, that in all 
that time it had not re-gained its wonted dark colour,but was only 
arrived at a green, deep enough , but not true nor very tranfpa° 
rent. 
This Obfervation being made in the fameVeflel that had been 
formerly employed, fuggefted 10 us an Enquiry , Whether the ad- 
vanced time of the year, which was the middle of Odiober , might 
not have an intereft in the flow and imperfeft fuccefs of this TryaL 
Exferiment the third. 
Some ftrong Spirit of Salt having been kept upon Filings of Cop- 
per till the folution was come to be of a dark brown colour,abouc 
threefpoonfulsof itby guefswasput into a Receiver that might 
hold eight or ten times as much : Being kept in vacuo ( if the time 
. be rightly rcmember'd) about half a year, it retain'd its colour, 
but the VefTe! being open'd and the External Air permitted a free 
accefs to it, the folution in about an hour was turn d into a fine 
tranfparent green,though no Precipitation of any muddy fubftance 
appeared by any Sediment to be made. 
Ppp 2 Exfe- 
