86 CULTURE OF THE SUGAR BEET. 



carbonate after Possoz and amnionic chloride after Monier, the latter to 

 give stability to the liquor. 



The liquor is made up as follows : 



Take 



Grams. 



Pure crystallized sulphate of copper 68. 7 



Rochelle salt 200. 



Dry pure carbonate of soda 100. 



Chloride of ammonium 6-87 



Mix with 500 or 600 cubic centimeters of water ; dissolve with heat 

 on a water-bath, cool and make up to one liter ; filter if necessary. The 

 standard of the liquor is 10cc=0.65 gram of sugar, but this should al- 

 ways be verified. Pellet found in using the liquor that the results 

 varied with the volume employed, but is exact for the following vol- 

 umes of fluid : 



Cubic* 

 centimeters. 



Cupric liquor 30 



Sugar solution with or without water 20 



In its application the copper liquor is mixed with the sugar solution, 

 and the whole heated upon the water-bath for half an hour ; the pre- 

 cipitate is collected upon a filter, washed, the suboxide of copper dis- 

 solved in hot dilute chlorhydric acid, oxidized by chlorate of potash or 

 permanganate, the excess of chlorine removed by boiling, and the so- 

 lution decolorized while boiling with standard solution of stannous 

 chloride. 



It may be proper to state here that for estimating sugar in solutions 

 by means of the copper liquor the cane sugar must be changed to in- 

 verted sugar by boiling from 30 to 40 minutes after addition of about 10 

 per cent, its volume of normal sulphuric acid (containing 10 per cent, 

 anhydrous acid) and subsequently neutralizing the acid by means of an 

 alkali. The sugar solution is then added to the boiling copper solution 

 until complete decoloration ; or, the process reversed, the copper solution 

 being added in excess to the boiling sugar solution, and the superfluous 

 cupric oxide determined by other methods, volumetrically or otherwise ; 

 or the cuprous oxide reduced may be collected and weighed, and the 

 sugar equivalent calculated from the amount found. 



But, as before stated, we do not propose here to give in full the chem- 

 ical methods employed for determining sugar, and we must therefore 

 refer the reader to works on analytical chemistry for further details. 



We now come to the methods of selecting seed and seed-bearers, and 

 the principles upon which they depend. Of all the experiments and in- 

 vestigations in the direction of improvement of this culture, none seem 



* Here, as in some other places in this report, I give the value in French weights 

 and measures, because they are generally employed in laboratory work and are of so 

 much greater convenience. Apparatus graduated to these measures may be obtained 

 from all dealers in chemical ijlassware. 



