( 285 ) 
As feveral Perfons may be willing to try a great 
many of Mr Hales Experiments, I thought proper to 
mention here, that the Experiments on Subftances that 
generate Air, made with the Glafs-Retort, are difHcult 
and tedious ; but a Musket-BarreJ with the Toudi-hole 
welded up, and then turn’d into a Semi-circle, makes a 
very commodious Iron-Retort, whofe clofe End being 
put into the Fire of a Smith’s Forge, will be fo heated 
with a little blowing, as to get the Air out of any 
Subftance in a very little time; having firlt twilled 
on upon the open End of the Barrel one End of a 
Leaden Syphon (which will be very tight, with only a 
little Sheep’s Leather between) whilft the other End 
of the Syphon goes up a little way into an inverted 
Chymical Receiver fill’d with Water. As the Air gets 
out of the Subllances dillill’d, it comes bubbling up 
thro’ the Water, which it deprelTes by its Bulk. N. B. 
Antimony and Sulphur muft not he made ufe of in this 
Barrel • hecaufe they will demetallize the Iron ; nor Lead^ 
hecaufe it ivill fweat out thrd the Iron, 
It appear’d by feveral Experiments, that the Air 
which was got out of the Subllances above-mention’d, 
was true permanent Air ; for it had, and, after many 
days, continu’d to have, both the Weight and Elallicity 
of common Air, of which a cubick Inch weighs J of 
a Grain, and after it had been comprefs’d, it wou’d ex- 
pand again to its former Dimenfions. 
Molt of that Air had a poifonous Quality, a Spar- 
row dying as it was put into the Air made of Oak, 
1 1 days after the faid Air had been made. So Mr. 
Boyle found the Air drawn by the Air-Pump from 
Bread and fome other Subllances, to have a poifonous 
Quality. 
Air generated by Indian wheat and by Peafe, and 
mofl: other Subllances, flaih’d when the Candle was 
applied to it. The 
