326 SORGHUM. 



Unlike the result with salt, which is but very little more soluble in 

 hot thau in cold water, when we evaporate a sugar solution in the open 

 air, we find that the whole will remain in solution ; and it is only 

 when we allow the solution to cool, that we have the excess of sugar, 

 which the water remaining is unable to hold in solution, crystallizing 

 out. 



The crystallization of sugar from its solution is a matter of the great- 

 est simplicity. Many interested or ignorant j^ersons have said, or 

 thought, that there was some secret device by which the sugar could 

 be secured ; and many have represented that, by one thing or another, 

 crystallization could be effected. The sugar may be obtained from a 

 saccharine juice by any body, provided only the conditions for secur- 

 ing it are maintained ; and these conditions are very few and very 

 simple, and will be made plain in what follows. 



It is also to be remembered, that no one is able to obtain sugar from 

 a juice if it is not there; and yet there are many whose claims are such 

 as to lead some to believe the contrary. 



Crystallization is also a means of purification. To illustrate this 

 point, suppose an ounce of common salt and an ounce of saltpeter (ni- 

 trate of potash) are together dissolved in a half pint of water, and the 

 solution is allowed to evaporate slowly. It will be found that the 

 crystals of salt and crystals of saltpeter will be separately formed as 

 the water evaporates, and if the two are carefully picked out, each will 

 be found to be entirely free from the other — that is, the salt crystal- 

 lizes out by itself and the saltpeter by itself Further, if to a solution 

 of sugar there is added a solution of another substance, which does 

 not crystallize, and evaporation takes place, the sugar will crystallize 

 out, leaving the other substance in solution. 



But it is found that the presence of certain sui3stances will prevent 

 the crystallization of sugar to a certain extent ; also, the presence of 

 certain others seems to favor or assist in the crystallization of sugar ; 

 while still other substances are apparently without any effect upon the 

 sugar present. The saccharine juice of plants, even after the most 

 careful defecation, is found to contain, besides the sugar, substances of 

 each of the three classes. The most important one is glucose and in- 

 verted sugar, more or less of which is always present, and which is es- 

 timated by sugar boilers as being able to hold in solution its own weight 

 of sugar. If, then, a pound each of glucose and sucrose should be 

 dissolved in a quart of water and the solution evaporated, it Avould be 

 found practically impossible to recover any of the sugar — but there 

 would be obtained a little over two pounds of molasses. So, too, the 

 salts or mineral matters present in the juice have each their specific 



