448 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



is about as strange a medley of half a dozen machines having apparently 

 totally diverse functions. Independently of its traction power — its main 

 employment — it is fitted up as a steam derrick, as a fixed engine to turn 

 the shafting in the workshops, and as a capstan to haul the ships about the 

 docks; and finally, it is now used as a very powerful steam fire engine 

 capable of throwing a jet to the top of the highest ship-building sheds; in 

 short, it can do anything, the dockyard laborers declare, short of talking, 

 and that it can do, after its own fashion, with its steam whistle. 



"When we saw it at work, it was removing a huge marine boiler from among 

 the scores of similar monsters stored in the depot. It seemed a marvel 

 how such a bulk of iron could be started at all; but by the use of tackles 

 and blocks it was first hauled clear of others, and then having been lifted 

 by jacks on to the traveling truck, the engine moved off with its load — 

 like an ant removing a grain of corn ten times as big and heavy as itself 

 — along the narrow tracks, in and out the timber and other impediments in 

 its way; round the various docks, without noise or friction, the great load 

 progressed until it finally reached its destination. The weight of the boiler 

 was about eight and twenty tons, which, together with that of the truck 

 and engine, made a total of forty-three tons; nevertheless, it went smoothly 

 over the yard, and, in consequence of its broad wheels, made even less 

 mark upon the paving than would a score of straining horses with their 

 hoofs flashing fire. 



"odd jobs. 



"As an instance of the odd jobs it is put to do, we may mention that a 

 particular balk of oaken timber being wanted from the middle of a stack, 

 an immense number of laborers were told off to haul it out. After many 

 efforts however, they gave it up, when the engine, happening to pass on 

 other work, the driver volunteered to get it out — a work done almost as 

 speedily as the pulling out of a double tooth, an operation it somewhat 

 resembled, inasmuch as the balk of timber was very irregular in form, and 

 must have required an awful tug to extract it from the stack. When any 

 steamer requires any repairs to her screw, this handy jack of the yard goes 

 down to tlie edge of the dock, fits up its derrick apparatus, and in a few 

 minutes the huge blades of the screw are lifted on to the quay wall. This 

 kind of work is varied sometimes by unloading timber from the ship's side 

 and taking it to the stack; or, with her capstan head, she lifts the heavy 

 chain cables from the holds of the men-of-war; and when the other laborers 

 have done their work, and the huge stationary engine of the yard is at 

 rest for the day, the traction engine comes up, plants herself firmly in the 

 shop where motive power is required for overwork, the band is slipped 

 over her driving-drum, and immediately the whole machinery of a depart- 

 ment is at work. Siie is constantly thus employed in the armor plate shed, 

 and, in consequence of the small expense at which she is worked, compared 

 with the large stationary engine, an immense saving accrues to the public 

 service. 



"the engine climbing hills. 

 >" Peihaps the most curious and interesting feature of the traction engine 

 is t!ic arrangement by which she is enabled to climb hills which horses 

 wiiii heavy loads could not attempt, and riot only to climb but to descend 



