VOL. XVIII.] PHILOSOPHICAL TRANSACTIONS. 609 



catalogue. To make the common spirit of nitre, you need only to mix 5 or 6 . 

 times as much clay as you take of nitre, and distil them in a retort, and you 

 may obtain a strong spirit of nitre this way, especially if you dephlegm it, and 

 rectify it to the best advantage. With this we have made an experiment of 

 accension succeed sometimes, though with great uncertainty; but the first, 

 which I call the compound spirit of nitre, is only to be relied on. 



This compound spirit seems to be the active principle that stirs up the oily 

 or more passive particles to take fire, which will more easily be agreed to, if we 

 consider that our compound spirit of nitre does not only consist of all those 

 igneous particles, to be found in common spirit of nitre, but that it has also all 

 those igneous particles which oil of vitrol contains in it, crowded into our spirit 

 of nitre made this way. For further illustration, let us consider what oil of 

 vitriol is ; it is a creature of the fire, that the sulphur, which is plentifully in 

 vitriol or in copperas, is accended, and afterwards distilled over in the form of 

 a liquor, which is a liquid sort of fire, as having many properties of it. If you 

 put it to water, it will make it boiling hot ; it burns not only linen and woollen 

 but wood, to a coal, and scarcely spares any thing. 



Nitre, the other ingredient of our spirit, is very susceptible of flame, which 

 also incorporates many igneous and corrosive particles, after it has so many 

 hours lain ignited in the fire, comes over by distillation, very highly impregnated 

 with the same fiery particles. — For nitre itself has no dissolving or heating 

 quality, but is a great cooler, and scarcely can be reckoned among acids ; but 

 after it comes out of the fire in the form of a spirit, it tears in pieces almost 

 all metals, and brings them to a sort of fusion, as actual fire does; it dissolves 

 animals and vegetables, and minerals, and has many effects of fire. Therefore 

 from the union of these two very fiery spirits results a much greater quantity of 

 igneous matter. 



That fire is very apt to incorporate with fluids, and even such as have had 

 but a small communication with it, an experiment which I formerly exhibited at 

 a meeting of the Royal-Society, makes probable. We took of spirit of wine, 

 highly rectified, a wine-glass half full, and placed a tender weather glass or 

 thermometer in the glass, and then put a spoonful of water to it ; this imme- 

 diately warmed the liquor, and made the weather-glass ascend 2 inches at least; 

 the liquor in the weather-glass subsided as the other mixture grew cold. I 

 made it more sensible to the touch by filling the palm of the president's hand 

 with spirit of wine, and putting a small quantity of cold water into the same 

 hand, which made it sensibly warm his hand, as well as others that made the trial. 

 But from this spirit, which is too volatile to endure much communication with 

 the fire, you may expect only a mild tepid heat ; I am apt to believe, that there is 

 VOL III. 4 Q 



