4g8 Early Developement of the Theory of Comhujlion. 



Secondly, that this aB'wn it performs not till the body be firft fufficiently heated, as we 

 find rcquifite alfo to the diflblution of many other bodies by feveral other menftruums. 



Thirdly, that this aSlion of dilTolution produces or generates a very great heat, and that 

 which we call fire ; and this is common alfo to many diflblutions of other bodies made by 

 menftruums, of which I could give multitudes of inftances. 



Fourthly, that this aElion is performed with fo great a violence, and does fo minutely aft, 

 and rapidly agitate the fmalleft parts of the combtijlible matter, that it produces in the 

 diaphanous medium of the air the aftion or pulfe of light, which what it is f have elfewhere 

 already {hewn. 



Fifthly, that the dijfolution of fulphureous bodies is made by a fubftance inherent, and mixt 

 with the air that is like it, if not the very fame, with that which is fixed in faltpetre, which, 

 by multitudes of experiments that may be made with faltpetre, will, I think, moft evidently 

 be demonftrated. 



Sixthly, that in this dijfolution of bodies by the air, a certain part is united, and mixt or 

 diflblved, and turned into the air, and made to fly up and down with it in the fame 

 manner as a metalline-^ or other body, diflblved into any menjlruums, does follow the motions 

 and progrefles of that meiiflruum till it be precipitated; 



Seventhly, that as there is one part that is diflblublc by the air, fo are there other parts, 

 with which the parts of the air mixing and uniting, do make a coagulmn or precipitation, as 

 one may call it, which caufes it to be feparated from the air ; but this precipitate is fo light, 

 and in fo fmall, or rarified, or porous clufters, that it is very volatile, and is eafiiy carried up 

 by the motion of the air, though afterwards, when the heat and agitation that kept it rarified 

 ceafes, it eafily condenfes, and commixt with other indiflbluble parts, it fticks and adheres to 

 the next bodies it meets withal •■, and this is a certain fait that may be extracted out of foot. 



Eighthly, that many indiflbluble parts being very apt and prompt to be rarified, and fo 

 whileft they continue in that heat and agitation, are lighter than the ambient air, are thereby 

 thruft and carried upwards with great violence, and by that means carry along with them not 

 only that/a/iw csmcrete I mentioned before, but many terreftrial or indiflbluble and irrarefiable 

 parts, nay, many parts alfo which are diflbluble, but are not fufft;red to ftay long enough 

 in a fufficient heat to make them prompt and apt for that aftion. And therefore we find 

 in foot not only a part that, being continued longer in a competent heat, will be diflblved by 

 the air, or take fire and burn, but a part alfo which is fixt, terreftrial, and irrarefiable. 



Ninthly, that as there are thefe feveral parts that will rarlfy and fly, or be driven up by 

 the heat, fo are there many others that, as they are indiflbluble by the aerial menjlruum, fo 

 are they of fuch fluggifti and grofs parts, that they are not eafily rarefied by heat, and there- 

 fore cannot be raifed by it ; the volatility or fixednefs of a body feeming to confift only in this, 

 that the one is of a texture, or has component parts, that will be eafily rarified into the form 

 of air, and to the other that it has fuch as will not, without much ado, be brought to fuch a 

 conftitution ; and this is that part which remains behind in a white body called aflies, 

 which contains a fubftance or fait which chemifts call alkali: what the particular natures of 



each 



