83 G NEW YOEK STATE MUSEUM 



These are made of cact iron, and consist of a frustum of a solid 

 cone called tbe core, working concentrically within the inverted 

 frustum of a hollow cone, both having on their adjacent surfaces 

 suitable grooves and flanges for breaking the stone as it passes 

 down between them, From the crackers the crushed cement is 

 carried by means of an elevator and conveyor to a sieve 11 feet 

 long and 10 inches wide, and about 50 meshes per inch. 25^ to 

 27/^ passes this sieve. That which does not pass the sieve goes 

 to horizontal stone mills, where it is ground between millstones, 

 after which the two lots of fine material are mixed, and then 

 packed in barrels for shipment. 



AJcron district 



One of the largest plants in the state is situated at this locality^ 

 viz the Cummings cement co. (pi. 80, 81); another large works 

 also near this town is the Union Akron cement co. (pi. 82, 83). 



The Cummings cement company has 675 acres of land, and 

 the cement bed is from 7 to 8 feet thick. The beds differ from 

 those at Rosendale in lying almost horizontally. The kilns are 

 34 feet high, eight of them being of rectangular cross-section, 

 9x22 feet in dimensions, and nine of them round, with a diameter 

 of 9 feet. During the calcination much of the cement rock be- 

 comes clinkered, and is separated and ground by itself to be sold 

 as Portland cement. 



At this works a general system of reduction is used, consisting 

 of 1) Sturtevant crushers; 2) Cummings pulverizers; 3) 10 run 

 of 42 inch underrunner millstones faced with chilled iron plates; 

 4) 10 run of 42 inch hard Esopus underrunner millstones. 



The material, as it is conveyed from one to another of these 

 sets of crushers, is made to pass over screens, whereby such 

 material as has been reduced to proper fineness is separated from 

 the mass and is spouted to a general conveyor, which finally re- 

 ceives the material from all the grinding machines and conveys 

 it to the packing house. Each set of crushers, while it furnishes a 

 part of the material, reduces the sizes of the unground portion 

 to such a degree that the material which is fed to the fourth 



