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instrument has been assisted by heat ; certain T am, that 

 t;his, which could be very easily contrived by means of 

 phosphorus, or any other hot substance applied to the 

 barrel, would give such a force as I doubt whether gun- 

 powder itself could produce. 



Every thing we see gives of its parts to the air, and; 

 has a little floating atmosphere of its own round it. 

 The rose is encompassed with a sphere of its own- 

 odorous particles ; while the nightshade infects the air 

 with scents of a more ungrateful nature. The perfume 

 of musk flies off in such abundance, that the quantity 

 remaining becomes sensibly lighter. A. thousand sub* 

 stances that escape all our senses we know to be there ;, 

 the powerful emanations of the loadstone, the effluvia of 

 electricity, the rays or light, and the insinuation of fire. 

 Such are the various substances through which we 

 move, and which we are constantly taking in at every 

 pore, and returning again with an imperceptible dis-- 

 charge. 



This great mixture of all earthly bodies is continually 

 operating upon itself; which, perhaps, may be the cause 

 of its unceasing motion ; but it operates still more 

 visibly upon such grosser substances as are exposed to 

 its influence ; for scarce any substance is found capable- 

 of resisting the corroding qualities of the air. The air, 

 say the chymists, is a chaos furnished with all kinds of 

 salts and menstniums ; and therefore it is, capable of 

 dissolving all kinds of bodies. It is well known that- 

 copper and iron are quickly eaten with rust ; and that 

 in the climates near the equator no art can keep them 

 clean. In those countries, instruments, knives and keys*, 

 though kept in the pocket, nevertheless are quickly en- 

 crusted ; and the great guns, v> ith every, precaution, 

 after some years, become useless. . Stones 'may be sup- 

 posed to be more easily soluble. The marble of which, 

 the noble monuments of Italian antiquity are composed, 

 although in one of the finest climates in the world, 

 nevertheless shew the impressions which have been made 

 upon them by the air. In many places they seem \vojfaa-. 



