men, &c. and wc may fafely conclude that a fmall additional 

 expenditure in the firft inftance, judicioufly applied, would turn 

 out a very eflential public advantage. 



I wiLi, next fuggcft an alteration in the fubftance and con- 

 ftrudion of the rollers, which may remedy fome of thofe defedls 

 I noted in the procefs of milling : Inftcad of marble or granite, 

 I propofe that they ihall be made of caft iron, as well as the 

 circular trough in which they move ; let the periphery of the 

 cylinder be divided into eight equal parts, alternately grooved 

 and plain, with two of the fluted divifions having their grooves 

 tranfverfc, the other two longitudinal, as in the annexed draw- 

 ing, where A reprefents the perfpedivc of the roller, and B is a 

 plan of its circumference, fhowing the difpofition of the compart- 

 ments and the direction of the grooves ; thefe grooves fhould be 

 an inch in breadth and a quarter of an inch in depth, with 

 their angles rounded off; the trough muft continue fnvooth, as in 

 the prefent praflice. The efFed propofcd from this conftrudion 

 is, that the alternations of the plain and fluted divifions, when 

 the rollers are in motion, will penetrate the fubftance of the 

 paftc, producing a more intimate connexion and intermixture of 

 the component parts than can poflibly refult from the equable 

 and fcarce interrupted progrefllon of one fmooth furface over 

 another ; by this operation becoming equivalent to many hours 

 labour. Where the private manufacturer is unwilling or unable 

 to afford new cylinders, he may break the continuity of the paftc, 

 by affixing a fmall but ■weighty harrow, with copper teeth, to the 

 axis of the roller, and following its diredlion in the trough. Should 



iron. 



