10 



usual wa>% a correction being- made in the results for the heat of com- 

 bustion of the block emploj^ed. 



DESCRIPTION OF SAMPLES OF FOOD MATERIALS. 



In the nulling of the hard spring wheat great care was taken to 

 secure representative samples. As in the former work, the milling 

 was carried on under the supervision of Mr. C. E. Foster, of Minne- 

 apolis, in one of the large flouring mills of that city. Two hundred 

 pounds each of the three different kinds of flour were obtained from 

 the mill. As soon as the samples were received at the laboratory 

 smaller samples were drawn for analysis. 



For the experiments with soft winter wheat difficulty was experi- 

 enced in securing samples of soft-wheat flours that were compara))le 

 with the grades of flour used in former work with hard spring wheat. 

 The samples of hard wheat used in 1899-1901 were exhaustively 

 milled and ver}!- little flour was left in the ))rau and middlings. 



The samples of soft wheat used in 1901-2 were, as is the custom with 

 such wheats, less exhaustively milled and more flour was left in the 

 offals. For this work sets of samples were o])tained from two differ- 

 ent milling companies, and in each case the different grades of flour 

 were from a single lot of wheat. 



A description of the different sorts of wheat used in the experiments, 

 and of the different grades of flour and milling products made from 

 them, is here given. These are the samples the analyses of which are 

 reported in Table 1. 



In addition to the various milling products mentioned, which are 

 standard grades, other grades may l>e obtained by subdividing a grade 

 or by mixing or blending two or more grades. Many of the flours 

 which are placed upon the market are mixtures of two or more stand- 

 ard grades of flour. 



No. 153. Hard Scotch Fife spring wheat, weighing 60 pounds per bushel; screened 

 but not scoured. This wheat is representative of the lianl spring wheat grown in the 

 Northwestern wheat regions of the United States. 



No. 154. Entire-wheat flour from hard spring wheat No. 153. This is the product 

 obtained by removing a i)ortion of the bran and grinding the remainder of the grain. 

 It includes the germ and other parts of the offal products which are excluded from 

 the patent grades of flour. This flour is coarser in texture and darker in color than 

 the patent and clear grades. The presence of fine bran particles prevents perfect 

 granulation. Such "entire-wheat" flour is sometimes called "pulverized graham" 

 or ' ' natural flour. ' ' 



No. 155. Graham flour from hard spring wheat No. 153. This consists of the 

 entire wheat kernel including bran, germ, and offal, ground into meal. ( Jraham flour 

 is practically wheat meal; no sieves or bolting cloths are employed in its manufacture, 

 and coarse particles of bran, etc., may be observed in the flour. 



No. 156. Straight patent flour from hard spring wheat No. 153. This includes the 

 first and second patent grades and the first clear or bakers' grade of flour described 

 below. Ordinarily about 72 per cent of the screened wheat is recovered as straight 

 patent flour. 



