TESTING SKIM-MILK, WHEY, CHEESE, ETC. 89 



graduate, which must be dry, with amyl reagent to the 

 6 cc. mark and pour into flask A. 



(5) Connecting the apparatus. Connect the appa- 

 ratus as shown in Fig. 36a, fill the condensing jacket 

 E with cool water to within one inch of the top (F 

 Fig. 36a) and remove the glass stopper. 



(6) Distilling the water from the butter. Heat the 

 bottom of flask A over the flame of the burner. The 

 butter soon melts, mixes with the amyl reagent, and 

 later the water passes as steam into the receiving bulb 

 (C), in which it is condensed and held. The conden- 

 sation in the graduated part 'of the tube must be care- 

 fully watched and the steam not allowed to go higher 

 that the 15 per cent, mark, in order to avoid risk of 

 losing water. If it goes higher 'than this, remove the 

 flame for a short time. If the mixture in flask A 

 shows a tendency to foam over, remove the flame. In 

 case of continued foaming, cool the flask and contents, 

 add about 2 cc. more of amyl reagent and continue 

 heating. 



(7) How to know when the distillation is complete. 

 When the mixture in the flask becomes brown and 



all crackling noise in boiling ceases, the water has all 

 been driven from the flask. This usually requires from 

 5 to 8 minutes. 



(8) Disconnecting apparatus. After completing the 

 distillation, flask A is disconnected from stopper B and 

 the glass stopper G is firmly placed in tube C. The 

 tube is then inverted, transferring the water from the 

 receiving tube into the graduated tube, care being 

 taken not to allow any water to be lost through the 



