400 GRAPE CULTURE AND WINE-MAKING. 



the concentration of tlie beet-juice is the method of effecting the 

 evaporation by means of the vacuum. Besides these there are 

 several other constructions of pans ; for instance, the one invent- 

 ed by Howard, another by Tischbein, and Daneck's apparatus. 



The first evaporation is usually continued until the juice gets 

 concentrated to about 10° or 12° of Beaume's scale. The vapors 

 arising during it will, by their ammoniacal smell, indicate the pres- 

 ence of many azotic parts. The juice is then drawn off by means 

 of a siphon, and conducted to the filtering apparatus. 



The first Filtration. — For this purjDosc bone or animal coal is 

 preferred. These, being filled into the apparatus, need a first clean- 

 ing of adhering dirty parts by cold water ; after this, a second wash- 

 ing by w^arm "water. Now the juice is j^ourcd upon them and left 

 for about half an hour in connection with them. When it has 

 passed through this oijcration, the juice is now subjected to 



The second Evaporation. — It will here be treated in the same 

 manner as at the first, and be found much purer and freer of lime 

 parts than before. It must be concentrated up to 20° or 22° B., 

 and is then allowed the 



Second Filtration in the same apparatus, and a like manipula- 

 tion as before. Asa matter of course, the juice, now being con- 

 centrated into a thick fluid, penetrates the coals very slowly, and 

 must be allowed ample time. 



The Animal Coal, or ^'' SpodiumJ'' — We need say nothing here 

 about the manner of making this, as it is a very simple and gen- 

 erally -knowm one. Well-charred coals weigh 40 to 42 pounds per 

 cubic foot. The net produce of the bones amounts to about 40 

 per cent, of their weight when fresh. The coal must have a deep 

 black color, a firm texture, and, touched by the lips, stick to them ; 

 if so, it may be considered good. Pulverizing it is not advisable. 



Boiling in ofi the refined Juice. 



This is generally effected in two different ways ; the one to be 

 called the boiling in to the string or clear proof, and the other 

 boiling in to the grain proof, and the boiling in of the sirup. 



In adopting the first, the juice is only concentrated to the crys- 

 tallizing point by applying a quick heat and a very careful man- 

 ipulation. This tends only to a slow and regular formation of 

 crystals, and to the producing of raw sugar in large crystals, that 

 still needs refining before it can be brought out for sale. Before 

 the mass gets too much concentrated, the kettle must be filled up 

 again with fresh juice, and this repeated. 



In the second case, which' will produce grain sugar (mclis) 

 merely, a firm and dense texture and small crystals are intended 

 in the sugar. The boiling must be continued until this proof is 

 attained. It generally turns out a very difficult affair, and must 

 be aided "by an addition of already-made crystal sugar at the ap- 

 proaching of the crystallizing point of the boiling juice. 



