OF TWO DIFFERENT LIQUIDS. 



35 



salt and water are at last uniformly distributed 

 throughout the liquid. 



If we fill one limb of the tube (Fig. 7), 

 as far as 0, with brine coloured blue, 

 and the other limb with water, we find, 

 in the course of a few days, the water 

 coloured blue, and the proportion of 

 salt in both limbs equal. It has been 

 mentioned at p. 16, that, in a tube 

 closed with bladder, filled with diluted 

 solution of salt, and exposed to evapo- 

 ration, the salt is not deposited in crys- 

 tals on the outer surface of the bladder till the 

 whole liquid in the tube has reached, in consequence 

 of evaporation, the maximum of saturation. The 

 water evaporates from the exterior of the bladder, 

 but no salt is deposited, as long as a liquid exists 

 within which can still dissolve salt ; and in this way 

 the heavier saline particles are distributed towards 

 the interior, and upwards through the whole liquid, 

 or, what amounts to the same, the lighter aqueous 

 particles, which can still dissolve salt, are distri- 

 buted downwards towards the external surface of 

 the bladder. 



This distribution of salt through water takes 

 place in the same manner as the conversion of bar 

 iron into steel. Rods of malleable iron, as is well 

 known, are kept ignited between strata of charcoal, 

 whereby the surface of the iron in contact with the 

 charcoal takes up carbon, and becomes a carburet of 



D2 



Experi- 

 ment shew- 

 ing the uni- 

 form mix- 

 ture of two 

 liquids. 



The distri- 

 bution of 

 salt through 

 water re- 

 sembles the 

 conversion 

 of iron into 

 steel by ce- 

 mentation. 



