SECOND LAW OF GRAVITATION. 113 



than the muscles ; so that while the muscular feeling 

 proceeds by atoms to which we can assign no mea- 

 sure of bulk or even of gravitation, the eye can take 

 cognizance only of collections of those atoms (the 

 smallest most likely amounting to countless mil- 

 lions), which have been known in their succession, 

 and compared and summed up by the mind from the 

 action of the muscles. So, our first knowledge of 

 matter is the knowledge of gravitation, and nothing 

 but gravitation ; but it is gravitation which we can- 

 not measure in the primary particle ; and therefore 

 it would be vain for us to inquire, or seek to be in- 

 formed of what gravitation is, because we have 

 pursued our analysis to its very beginning, and there 

 we equally speak truth when we say " gravitation 

 is matter," and " matter is gravitation ;" for to our 

 perception they are one and the same. 



The second law of gravitation, which it is neces- 

 sary for every useful observer of nature to know 

 and to bear in mind, is the law of its variation. 

 That law is no variation in the quantity of gravita- 

 tion itself, because, being the primary quality of 

 matter, gravitation is as indestructible, either in 

 whole or in part, as matter itself, and can be de- 

 stroyed only by the same power that made it. 

 When we divide matter, we divide gravitation along 

 with it ; but there is no ingenuity in man, and we 

 know of no process in nature by which any one 

 portion of material substance can be deprived of 

 the least shade of its material quantity. The little 

 particle of water, while it is rising in vapour through 

 the dry air, so fine that no eye or instrument can 

 recognise its existence, has the quality of gravita- 

 tion as perfect as if it were dashing down the rocks 

 in the mighty flood at Niagara; and the smoke 

 which ascends upward in the free air would, in a 

 vessel from which the air had been all pumped out, 

 lie at the bottom the same as a stone. The cork 

 that floats on the surface of water has the very 

 K2 



