68 On Crystallography. 



btned with eacb other in the salt, according to a certain 

 proportion and a determinate arrangement. Each cube 

 which we take from this saU is an aggreE,ate, and the con- 

 nection and arrangement of molecules is the saiTie as in the 

 whole mass. But the subdivision of the salt into cubes suc- 

 cessively smaller, has necessarily its limits; and if we were 

 possessed of organs and instruments of sufficient delicacy 

 for pushing this division as far as it would go, we should 

 even obtain cubes incapable of being subdivided without 

 being analysed, i. e. without insulating the two principles, 

 the junction of which constitutes the essence of the salt. 



Hence we conclude, that we may consider in this salt 

 (and the same may be said of all the minerals) molecules of 

 two orders : the first, which we shall call eleinentary mole- 

 cules, and which are in the present case, on one hand thosa 

 of the acid, and on the other those of the soda; the second, 

 to which we shall give the name of integrant molecules, and 

 which are in the same case, the smallest cubes which can be 

 obtained separately, without the nature of the salt being de- 

 stroyed. The elementary molecules have doubtless regular 

 and constant forms also for each species t^f acid, alkali, &c., 

 " and those of one species adapt themselves to those of the 

 ^ other, forming small compartments whence result the inte- 

 grant molecules. 



We shall suppose that these last moiemlt's were similar 

 to the solid ones procured from a mineral by dividing it me- 

 chanically. Of this wc are not physitally certain, since 

 these molecules escape our observation from their extreme 

 tenuity. But in the study of Nature we cannot act more 

 wisely than to adopt this principle : That things are to be 

 considered precisely as they present themselves to 02ir obser- 

 vation. The ultimate perceptible results of the mechanical 

 division of minerals, if they do not give us the figure of the 

 - true integrant molecules employed by Nature, represent them, 

 at least with respect to us; nearly as the substances which 

 chemists can no longer analyse further, arc simple siibntanccs 

 with respect to them, although in reality they may still be 

 susceptible of decomposiiion. 



It 



