NOTES ON FLOUR-STRENGTH. 173 



In washing out the dough to obtain the gluten, impurities 

 were noticeable, and it would seem that the usual time 

 (one hour) for standing in dough before washing out is 

 insufficient in the case of coarse products, as the dough 

 during the washing out felt gritty. These middlings were 

 then sifted in order to separate them into finer and coarser 

 grades. 



The first portion was retained by a No. 11 dressing silk 

 (112 meshes to the linear inch) and passed through a No. 9 

 dressing silk (94 meshes to the inch). The second portion 

 was retained by the No. 9 silk and passed through a No. 7 

 silk (80 meshes to the linear inch). The third portion was 

 that which was retained by the No. 7 silk and passed 

 through a No. 5 silk (64 meshes to the inch). We thus 

 obtained from the original coarse semolina four different 

 grades of varying fineness of division. These behaved 

 towards water as shown in the following table: — 



Water absorption n1 . 

 quarts per 200 lbs. ^ ute n. 



Original coarse semolina 45'5 9*66 



A. Portion passing through No. 5 44*0 9*78 



but not through No. 7. 



B. Portion passing through No. 7 46*6 10*07 



but not through No. 9. 

 O. Portion passing through No. 9 47*0 



but not through No. 11. 



The finer portion of the semolina had a higher water 

 absorbing power than the coarser, and the original semo- 

 lina stands about half way between the finer and coarser 

 portions in this respect. The actual proportions of fine 

 and coarse particles were not determined, so that the exact 

 average could not be calculated. 



The effect of fineness of division upon the water absorbing 

 power was even more apparent when the above products 

 were reduced to flour. Each of the portions A, B, and O, 

 and the original coarse semolina was put through the smooth 



