revolve once in twenty-four hours. In this way no great'strain was 

 put upon the clock, which was an ordinary one-day timepiece. This 

 arrangement is not shown in the figure. 



In order to obtain results which shall be strictly -comparable it is 

 essential that all the samples of wheat are ground to the same degree 

 of fineness. On the small scale this is somewhat troublesome, as the 

 sifting is by no means easy. It was found after several trials that 

 if the flour was passed through a " 90 " sieve the results appeared 

 satisfactory. Finer grinding than this is difficult without special 

 appliances. As an example of the effect of the fineness of grinding 

 and sifting on the results of the test the following figure will serve. 

 Some native flour, which is not particularly finely ground, was taken ; 

 some of this was sifted through a " 90 " sieve. Portions of the original 

 flour, that which passed through the sieve and that portion which 

 was retained by the sieve were taken, and the amount of gas given 

 off during fermentation was determined in each. The results were 

 as follows : * 



Cubic CctiUmetrei. 



Flour as purchased. Gas evolved ... 441 451 



Portion passing "90" sieve 471 483 



Portion retained by "90" sieve ... 317 352 



From these figures it is evident that uniformity in grinding and 

 sifting is desirable and even essential if reliable and comparable 

 results are to be obtained. 



In Figure 3 are shown the results obtained by this method with 

 three typical Egyptian wheats. It will be noticed that judged by 

 this method Safidi wheat appears as a strong wheat. Fayumi would 

 be classed as medium, while the Hindi wheat, as usually grown in 

 this country, is a very weak wheat. A number of samples of wheat 

 of various kinds were examined ; at the same time the nitrogen content 

 was determined. These results, together with the percentage of bran 

 and the weight of 1,000 seeds, are shown in Table I. This last figure 

 serves to show whether the wheat was well nourished. It will be 

 noticed that the strongest wheat, as estimated by the volume of gas 

 evolved, is the Upper Egypt wheat known as Gawi. This is a very 

 liard and horny wheat, giving a flour of a distinct yellow colour. The 

 dough made from this wheat is also strongly coloured. 



