j a Great Tenacity of Cotton , Silk, &c. [Book I. 



ceflary for the fupport of life, yet how infinitely re- 

 moved are thefe from our infpection ! Some idea, 

 however, may be formed of the aftonifhing power of 

 matter in this refpect, from inftances which are fur- 

 nilhed by all the moft common experiments of philo- 

 fophy. A pound of even fo grofs a fubflance as cot- 

 ton, may be fpun into a thread upwards of one hundred 

 miles in length * j and Mr. Boyle fpeaks of a thread 

 of filk 300 yards in length, which weighed no more 

 than three grains and a half. This, however, is ftill 

 furpafTed by the amazing ductility of gold ; fixteen 

 ounces of which would completely gild a wire fuffi- 

 cient to circumfcribe the whole globe of the earth, 

 though that quantity of the metal might be contained 

 ill a cube of not more than an inch and a quarter in 

 diameter. The metallic particles are yet more mi- 

 nutely divided in the acid folutions. A fmall piece 

 of the fait of filver, which is filvcr already divided 

 3nd united to the nitrous acid, not larger than a com- 

 mon pin's head, will tinge a quart of water of a milky 

 colour j and even the hundredth part of a grain of 

 copper will impart a fenfible blue to a pint of the fame 

 fluid. 



It is well known that camphor, mufk, and other 

 odoriferous fubftances will emit particles that fhall 

 powerfully affect the organs of fcent, and fhall com- 

 municate their peculiar fragrance to the furrounding 

 air for a confiderable fpace of time, without any per- 

 ceptible decreafe of weight. The extreme rarity of 

 the elaftic fluids is a further proof of the divifibility 

 of matter. Gunpowder, when exploded, expands to 

 244 times its bulk when in a foiid ftate ; and wa- 

 ter in the (late of vapour occupies a fpace 1800 



* Repofuory, vol. ii, p. 52. 



times 



