lis THE CEREALS IN AMERICA 



the material is mashed, rather than torn as in the bun- stones 

 There were in the United States in 1900 about two and one-hali 

 as many pairs of rolls as nms of stone. 



The separation of the different portions of the grain is accom- 

 plished partly by gravity and partly by bolting cloth of different 

 sized meshes. The endosperm breaks up into spherical or 

 cubical particles, while the other portions are more or less flat- 

 tened, forming comparatively larger dimensions and having a 

 less specific gravity. 



177. The Purifier. — Formerly, and by what is now known as 

 the old process of milling, wheat was merely ground as finely as 

 possible and then bolted. By the introduction of the middlings 

 purifier two steps have been added to the process, viz., puri- 

 fying and regrinding. 

 The details of this 

 "new" process are 

 elaborate and compli- 

 cated but the principles 

 involved are quite sim- 

 ple. The thoroughly 



The middlings purifier, which has greatly influenced cleaned wheat, whether 



the wheat industry. j-qHs or burrs are used, 



is first ground, or rather 

 granulated coarsely, resulting in three products : flour of a low 

 grade, middlings and bran. The middlings are now put through 

 the purifier in order to extract dirt, bran and fuzz. They are 

 then ground by a more or less gradual process, depending 

 upon the construction of the mill, and finally bolted. It is from 

 these middlings thus purified that the highest grade (so-called 

 patent) of flour is made. 



The introduction of the purifier in 1870 revolutionized the 

 process of milling, and made the use of the hard spring wheats 

 of the Northwest of the highest value, while formerly they were 

 of the least value for the production of high grade flour. 



