146 HISTORY OF 



without. Kircher used to show, in his Museum, 

 a phial of water, that had been kept for fifty years 

 hermetically sealed ;* during which it had de- 

 posed no sediment, but continued as transparent 

 as when first it was put in. How far, therefore, 

 it may be brought to a state of purity by distilla- 

 tion, is unknown ; but we very well know, that 

 all such water as we every-where see, is a bed in 

 which plants, minerals, and animals, are all found 

 confusedly floating together. 



Rain water, which is a fluid of nature's own 

 distilling, and which has been raised so high by 

 evaporation, is, nevertheless, a very mixed and 

 impure substance. Exhalations of all kinds, whe- 

 ther salts, sulphurs, or metals, make a part of its 

 substance, and tend to increase its weight. If we 

 gather the water that falls after a thunder-clap, 

 in a sultry summer's day, and let it settle, we 

 shall find a real salt sticking at the bottom. In 

 winter, however, its impure mixtures are fewer, 

 but still may be separated by distillation. But as 

 to that which is generally caught pouring from the 

 tops of houses, it is particularly foul, being im- 

 pregnated with the smoke of the chimnies, the 

 vapour of the slates or tiles, and with other im- 

 purities that birds and animals may have deposit- 

 ed there. Besides, though it should be supposed 

 free from all these, it is mixed with a quantity of 



* Hermetically sealing a glass vessel, means no more than heating the 

 mouth of the phial red hot ; and thus, when the glass is become pliant, 

 squeezing the mouth together with a pair of pincers, and then twisting it six 

 or seven times round, which effectually closes it up. 



