206 Oi\ WATER AND WATKKING PLANTS. 



well stopped, that the least fly may not get into them, and they 

 must be made of such stuff as will not corrupt, such as glass or 

 clay. 



" But for standiug water in ponds or marshes, that is corrupt- 

 ed two ways. 



" By the nature of the soil, which often abounds with noisom 

 sulphur, whereby the water is impregnated and comes to smell 

 in warm weather ; as it does at Amsterdam, not only in the 

 trenches, but wherever the ground is opened for the foundation 

 of houses. This putrefaction is owing to the soil, and not to the 

 water. 



" By the nasty things that are thrown into it, or bodies of in- 

 sects which die in it; as also by the eggs of flies, which are drop- 

 ped about wherever they go, and breed worms. Water is cor- 

 rupted in wooden vessels, especially at sea, by the sulphureous 

 parts of the wood, and by uncleanly things, as flies, eggs, &c. 



" Water penetrates the pores of those bodies, whose pores 

 are wide enough to receive its particles. Thus it enters the pores 

 of sugar and salts, so as to separate and quite dissolve their par- 

 ticles; but it cannot get into the pores of stones, or but a very 

 little way ; so that it only wets the surface, without diluting 

 them ; hangs on the outside of them because they are rough, and 

 because the extremities of their pores are open a little way. But 

 such bodies when they are wet are soon dried in the air, because 

 the motion of the airy particles, carries off the soft and smooth 

 particles of the water. 



It is observable that if bodies rubbed over with oil or fat be 

 dipt in water, they get very little wet, because the roughness of 

 their surface wherein the water should hang is smoothed and 

 made even by the fat, and the mouths of the pores are closed up, 

 so that there is nothing left for the watery particles to hold by, 

 and therefore they must needs slide off. 



" Dr. Cheync observes, that the quantity of water on this side 

 of our globe does daily decrease ; some part thereof being every 

 day turned into animals, metalline, mineral and vegetable sub- 

 stances, which are not easily dissolved again into their compon- 

 ent parts ; for if you separate a few particles of any fluid, and fas- 

 ten them into a solid body, or keep them asunder one from an- 

 other, then they are no more fluid : for a considerable number 

 of such particles are required to produce fluidity. 



" Most liquors are formed by the cohesion of particles of dif- 



