BOOK II.] EXPANSION OF MATTKB. 521 



substances, the second of vegetables, and the third of animals), 

 is placed, as it were, before the eyes by many reducing 

 instances. 



Again, it is clear that the more refined tissue and conformation 

 of things (though forming the whole body of visible or tangible 

 objects) are neither visible nor tangible. Our information, 

 therefore, must here also be derived from reduction to the 

 sphere of the senses. But the most radical and primary dif 

 ference of formation depends on the abundance or scarcity of 

 matter within the same space or dimensions. For the other 

 formations which regard the dissimilarity of the parts contained 

 in the same body, and their collocation and position, are 

 secondary in comparison with the former. 



Let the required nature then be the expansion or coherence of 

 matter in different bodies, or the quantity of matter relative to 

 the dimensions of each. For there is nothing in nature more 

 true than the twofold proposition, that nothing proceeds from 

 nothing and that nothing is reduced to nothing, but that the 

 quantum, or sum total of matter, is constant, and is neither in 

 creased nor diminished. Nor is it less true, that out of thia 

 given quantity of matter, there is a greater or less quantity, 

 contained within the same space or dimensions according to the 

 difference of bodies; as, for instance, water contains more than 

 air. So that if any one were to assert that a given content of 

 water can be changed into an equal content of air, it is the same 

 as if he were to assert that something can be reduced into 

 nothing. On the contrary, it any one were to assert that a 

 given content of air can be changed into an equal content of 

 water, it is the same as if he were to assert that something can 

 proceed from nothing. From this abundance or scarcity of 

 matter are properly derived the notions of density and rarity, 

 which are taken in various and promiscuous senses. 



This third assertion may be considered as being also suffi 

 ciently certain ; namely, that the greater or less quantity of 

 matter in this or that body, may, by comparison, be reduced to 

 calculation, and exact, or nearly exact, proportion. Thus, if one 

 should say that there is such an accumulation of matter in a 

 given quantity of gold, that it would require twenty-one times 

 the quantity in dimension of spirits of wine, to make up the 

 same quantity of matter, it would not be far from the truth. 



The accumulation of matter, however, and its relative quantity, 

 are rendered sensible by weight ; for weight is proportionate 

 to the quantity of matter, as regards the parts of a tangible sub 

 stance, but spirit and its quantity of matter are not to be com 

 piled by weight, which spirit rather diminishes than augments. 



We have made a tolerably accurate table of weight, in whii-h 

 we have selected the weights and size of all the metals, tiie 



