THEORY OF FERMENTATION 341 



Phosphate of potassium 0.4 grammes 



Sulphate of magnesium 0.4 



Sulphate of ammonia 0.2 



(i gramme = 15.43 grains.) 



On March 23rd, 1875, we filled a 6 litre (about n pints) 

 flask, of the shape represented in FIG. n, and placed it 

 over a heater. Another flame was placed below a vessel con- 

 taining the same liquid, into which the curved tube of the 

 flask plunged. The liquids in the flask and in the basin 



FIG. 



were raised to boiling together, and kept in this condition 

 for more than half-an-hour, so as to expel all the air held 

 in solution. The liquid was several times forced out of the 

 flask by the steam, and sucked back again; but the portion 

 which re-entered the flask was always boiling. On the fol- 

 lowing day when the flask had cooled, we transferred the 

 end of the delivery tube to a vessel full of mercury and 

 placed the whole apparatus in an oven at a temperature vary- 

 ing between 25 C. and 30 C. (77 F. and 86 F.) ; then, 

 after having refilled the small cylindrical tap-funnel with 



