Temperature of hot blast............................................... 600°

Density of blast and of refining furnace.... 2½ to 3 lbs. per sq. in. Revolutions of puddling rolls per minute, 60; rail rolls, 100; rail saw, 800.

Horse-power (indicated) required for different Processes.

Blast furnace.....................

60

Refining furance....................

26

Puddling rolls with squeezers and shears.........................

80

Rail rolling train...............

260

Small bar train.............

60

Double rail saw.............

12

Straightening.....................

7

Rolling-Mills. 10 tons bar iron per day...... 80 | Plates, for each sq. ft. rolled. 5