162 AGGREGATION. 



a solid disappears, it passes through the liquid state 

 into vapour. 



So also, in the formation of new aggregations, 

 whether these be liquid or solid, or whether they 

 be what we call simple or what we call compound, 

 the primary state that in which the combination 

 or the aggregation begins is the state of air. It 

 is of no consequence whether the result be what 

 we call a ne\v body, or what we call the repairing 

 of an old one ; for the process of nature, however 

 it may vary in appearance, and whether to our 

 senses it be visible or invisible, is always the same, 

 Air with air is the only state of intimate union 

 which we know of that is primary, or that of atom 

 with atom, so that the compound or the mass may, 

 to our observation, appear one substance. 



Liquidity is a weakening of the cohesion of par- 

 ticle with particle ; but it is not, in the case of any" 

 liquid with which we are acquainted, a total suspen- 

 sion of that cohesion. There is no liquid but which 

 can form into drops, or be poured in a continued 

 and connected stream, which shows that the par- 

 ticles have still some attraction, as we call it, for 

 each other. They are not quite subdued, but, like 

 the bent bow, retain their capacity of returning from 

 the bend. Some, no doubt, pass very soon into va- 

 pour. In dry air, single drops of ether will evapo- 

 rate before they reach the ground from the usual 

 height of the hand ; and there are many instances 

 of showers being evaporated in their fall, and never 

 reaching the ground ; indeed, most showers are less 

 or more evaporated in their falling by the warm air 

 near the sheltered and low places ; and thus there 

 falls more rain even at the top of a place of ordinary 

 elevation, than on the same surface of the ground 

 on which the house stands. But still, even the 

 most rapid of those evaporations takes some time, 

 and the cohesion of the particles forms a drop at 

 the beginning, in opposition both to the liquidity and 



