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THE ROYAL SOCIETY OF CANADA 



The following table presents the results from such a comparison 

 with the electric oven and the water oven. 



Comparison of results from Vacuum oven at 100° C. with those from Electric air oven at 

 100° C. and at 110° C, and Water oven at 91° C. 



Series A. In series A the first readings were obtained from weigh- 

 ings at the end of 5 hours. Immediately after weighing the dishes 

 were replaced in the vacuum oven and heated for a further period of 

 5 hours, cooled and re-weighed; the results furnished the second 

 readings. It will be observed that the percentages of the second 

 reading are slightly higher than those of the first. 



Series B. From the results of series A it might be concluded that 

 if a sample of fîour were heated in the vacuum for 5 hours, then in 

 an air oven and again in the vacuum oven, the results from this second 

 heating in the vacuum oven would be slightly higher than those from 

 the first five hours heating, provided there was no oxidation in the 

 air oven. The data of series B are from such an experiment; they 

 indicate that there has been no oxidation in the air oven, since in such 

 a case the third reading would have been lower than the first. 



Series C. This series is a repetition of the work in Series B, with 

 the exception that a temperature of 110°C. was used in the electric 

 air oven. The several readings are in accord with those of series B 

 and prove that no oxidation of the flour at 110°C. takes place. 



Series D. This series is similar to B and C, with the exception 

 that the water oven was used in the place of the electric air oven. 

 Considering the results from the standpoint of throwing light upon 

 possible oxidation in the water oven, it will be observed that the 

 percentages of the third readings are practically identical with those 

 of the first. This might be interpreted as indicating a certain degree 



