THE EARTH. 77 



just as accident has formed them, yet it heaved in great waves like 

 water. Upon agitation, a heavy body will sink to the bottom, and 

 a light one emerge to the top. There is no reason, then, to suppose 

 the figure of the parts of water round, since we see their fluidity very 

 well imitated by a composition, the parts of which are of various forms 

 and sizes. The shape of the parts of water, therefore, we must be 

 content to continue ignorant of. All we know is, that earth, air, and 

 lire, conduce to separate the parts from each other. 



Earthy substances divide the parts from each other, and keep them 

 asunder. This division may be so great, that the water will entirely 

 lose its fluidity thereby. Mud, potter's* clay, and dried bricks, are but 

 so many different combinations of earth and water, each substance in 

 which the parts of water are most separated from each other, appear- 

 ing to be the most dry. In some substances, indeed, where the parts 

 of water are greatly divided, as in porcelain, for instance, it is no easy 

 matter to recover and bring them together again ; but they continue 

 in a manner fixed and united to the manufactured clay. This cir- 

 cumstance led Doctor Cheney into a very peculiar strain of thinking. 

 He suspected that the quantity of water, on the surface of the earth, 

 was daily decreasing. For, says he, some parts of it are continually 

 joined to vegetable, animal, and mineral substances, which no art can 

 again recover. United with these, the water loses its fluidity ; for if y 

 continues he, we separate a few particles of any fluid, and fasten them 

 to a solid body, or keep them asunder, they will be fluid no longer 

 To produce fluidity, a considerable number of such particles are re- 

 quired ; but here they are close, and destitute of their natural proper* 

 ties. Thus, according to him, the world is growing every day harder 

 and harder, and the earth firmer and firmer ; and there may come a 

 time when every object around us may be stiffened in universal frigidi- 

 ty ! However, we have causes enough of anxiety in this world already, 

 not to add this preposterous concern to the number. 



That air also contributes to divide the parts of water, we can have 

 no manner of doubt ; some have even disputed whether water be not 

 capable of being turned into air. However, though this cannot be 

 allowed, it must be granted, that it may be turned into a substance 

 which greatly resembles air (as we have seen in the experiment of the 

 relipile) with all its properties; except that, by cold, this new-made 

 air may be condensed again into water. 



But of all the substances which tend to divide the parts of water, 

 fire is the most powerful. Water, when heated into steam, acquires 

 such force, and the parts of it tend to fly off from each other with such 

 violence, that no earthly substance we know of is strong enough to 

 confine them. A single drop of water, converted into steam, has been 

 found capable of raising a weight of twenty tons ; and would have 

 raised twenty thousand, were the vessel confining it sufficiently strong. 

 and the fire below increased in proportion. 



From this easy yielding of its parts to external pressure, arises the 

 art of determining the specific gravity of bodies by plunging them in 

 water; with many other useful discoveries in that part of natural phi" 

 'osophy, called hydrostatics. The laws of this science, which Ai- 

 thimedes began, and Pascal, with some other of the moderns, have 



