Royal Society. 123 
Take of any of the eflential oils, fet down in the catalogue, one 
part, of the conapound fpirit of nitre two parts, ( and thele may 
be drachms) and they will, with great celerity and noiie, pro- 
duce a flame, which lafts a very little while, but leaves an infipid 
Caput Atonuutn^ as light and taftlefs as a cobweb. 
Note, I. This experiment fliould be made under a chimney, 
or any convenient draught, that ib the ofFenfive fleams may eva- 
porate. 2. A gally-pot, capacious enough to hold 4 or 5 ounces 
of water, may be a convenient veffel for this experiment, if you 
only ufe the abovementioned proportion 5 but if you ufe larger 
quantities, then you mult enlarge the vefTel. 3. You mufl put 
the oil into the galley-poc firft, becaufe the fpirit, being heavier, 
does the better pafs thro' the oil, and make a more expeditious 
mixture, and it mull: not be dropped in gradually, but all at 
once. 4. Take care not to hold your head too near the galley- 
pot, leaft the ludden explolion of the matter ihould throw up 
Ibme of it into your face. 5. The compound fpirit will lole 
much of its virtue, if kept too long. 
To prepare the compound Ipirif of nitre, take of faltpetre and 
oil of vitriol equal parts, and dillill thele out of a retort in a good 
land-furnace, fo that the fand continue red-hot for fome hours, 
for the fire cannot be too great , the fumes will arile of a very 
deep red colour, and will lettle in the receiver in the form of a 
liquor, which mull be carefully prelerved from the air, this being 
the fpirit with which all the experiments were made, which are 
referred to in the catalogue. To make the common fpirit of ni- 
tre, you need only mix 5 or 5 times as much clay as you take of 
nitre, and diftil them in a retort, and you may obtain a ftrong 
fpirit of nitre this way, elpecially if you dephlegmate and rectify 
it to the bell advantage 5 with this Dr. Slare made an experi- 
ment of accenfion, that fucceeded fometimes , but with great un- 
certainty, the firll, which is called the compound fpirit of nitre, 
being only to be relied on 5 this compound fpirit leems to be the 
a£live principle that ftirs up the oily, or morepaflive particles to 
take fire 5 which will more ealily be allowed, if we conlider that 
the compound fpirit of nitre does not only confifl of all thole ig- 
neous particles to be found in common fpirit of nitre, but that it 
has alio thole fiery particles, which oil of vitriol contains, croud- 
ed into the fpirit of nitre. For farther illullration let us confider, 
that oil of vitriol is a creature of the fire, that the fulphur. 
which is plentiful in vitriol, or copperas, is accended, and after- 
wards diftilled over in the form of a liquor, which is a liquid 
fort of fire, as having many properties thereof^ if you put it to 
Q_ 2 warerj 
