220 ANNUAL KEI'ORT SMITHSONIAN INSTITUTION, 1910. 



sort, one of these buttons is pushed, which shuts off the steam and 

 stops the engine. Nearly one hundred of these stops have been in- 

 stalled in plants of the American Steel & Wire Co, 



The push buttons operate by electricity — and the small wires which 

 carry the current to the engine-room may be broken, the push buttons 

 may be get out of order, or the batteries develop defects ; here, if any- 

 where, "eternal vigilance" is the price of safety, and we have ar- 

 ranged that the daily shutting down of the engines shall be by means 

 of these buttons, and that once a week each button shall be pushed 

 with a man at the engine throttle to see that it works properly — ^the 

 speed limit tried, the voltage of the batteries taken, and the lines 

 tested for breaks ; all of this being reported on a printed form. In 

 several places butter-fly valves have been placed in steam lines to 

 engines — ^that is, a valve which closes instantly by pulling a lever, 

 and chains or wire ropes are carried from this lever to convenient 

 points for stopping the engine from a distance. 



MOTOR STOPS. 



In departments driven by electricity, we have motor stops cor- 

 responding to the automatic engine stops described. In some cases 

 these are arranged to operate by push Ijuttons, and in others a rope 

 is carried directly from the machinery to the switch controlling the 

 motor, so that the switch can be pulled by means of the rope in case 

 of emergency. Plate 3 shows a series of machines having a stop of 

 this sort. There is an operator at each set of rolls. Recently when 

 one of them had his hand caught he cried out, and several of his 

 fellow operators pulled the rope with such vigor that the switch 

 was torn bodily from the board. The motor was stopped so quickly 

 that only the tips of the injured man's fingers went into the rolls, 

 whereas his whole hand would undoubtedly have been crushed but 

 for this safety stop. 



ELECTPJC TRAVELING CRANES. 



Electric cranes have been called the " giant laborers " of the mills. 

 They pick up a ladle weighing 20 tons, with 50 tons more of molten 

 iron inside it, carry, and pour it as readily as if it were a cup of tea. 

 Heavy rolls and housings used in the mills are lifted out and replaced 

 by them, and in many departments all of the daily tonnage is handled 

 one or more times by cranes. They are excellent servants, but some- 

 times they blunder, and a ladle of steel upset may mean disaster to a 

 dozen men. There are gears and wheels which mangle; and 20, 30, 

 40 feet of space underneath the man who falls from a crane bridge. 



Some one has said that the education of a child should begin with 

 its grandparents; certainly the best time to safeguard a crane is 

 before it is bought. This method can be used when new machinery 



