Photograph courtesy Philadelphia Commercial Museum 



THE HOLD OF A LAKE STEAMER WHICH BRINGS THE ORE FROM THE MIXES OF 

 MINNESOTA TO THE STEEL INDUSTRY OF PENNLAND 



The huge buckets can scoop up two 4-horse wagon-loads of ore at a time. 



In some plants the packing machinery is 

 far from the least interesting part of the 

 equipment. Leading from the bin is a 

 large hopper with an automatic weighing 

 machine. The barrel, with the head in 

 place, but having a two or three-inch hole 

 'in the center, is put in position, a big fun- 

 nel connecting the head-bung with the 

 hopper. Through this the cement flows 

 until both the barrel and the funnel are 

 full. 



The barrel is then lifted away by a ma- 

 chine and set on a mechanism that may 

 be depended on to pack the cement tight. 

 Overhead is a shaft made on the prin- 

 ciple of that which drives the pistons of 

 an automobile engine. As it turns around, 

 it lifts the barrel several inches, and then 

 lets it drop, repeating the process about 

 as rapidly as one can count. When this 

 shaking process is finished all of the ce- 

 ment has been driven out of the funnel 

 and into the barrel, which is now packed 

 as tightly as if it were solid rock. A piece 

 of wood is nailed over the hole, and the 



steel-hooped barrel, weighing nearly four 

 hundred pounds, is ready to be trans- 

 ported. 



With three separate operations of con- 

 verting hard solids of considerable size 

 into dust, at the rate of thousands of bar- 

 rels a day, one would naturally think of 

 a cement plant as the dustiest place in all 

 the world. Yet in many modern Port- 

 land cement plants there is not as much 

 free dust floating around as one finds in 

 the average old-fashioned country grist- 

 mill. Indeed, there are some plants so 

 free from dust that one might go through 

 them in a dress suit and come out with- 

 out serious need of a whisk-broom or a 

 clothes-brush. 



The shearing strength of concrete made 

 from Portland cement is rising to such 

 unexpected heights that the experts sug- 

 gest that the day may not be far distant 

 when architectural specifications will per- 

 mit the same lightness of construction 

 that is accepted with steel. A world 

 shortage of steel might be compensated 



387 



