ON THE FORTH BRIDGE WORKS. 879 
Rohastins with all the other appliances have been provided, similar to those 
to be adopted for lifting the internal viaduct already described. 
A hoist is provided for lifting from the ground underneath the main 
girders the whole of the stone, &c., required in building the piers upwards 
from their present level. This material will be raised while on trollies, 
and while still on these run along the temporary road laid on the bottom 
of the main girders to any or all of the piers. On arrival at any pier it 
can be raised and laid in position by a pair of small runners fixed to the 
girders immediately above each pier. The power used for raising, lower- 
ing, or traversing either way being transmitted through special horizontal 
winches driven by a rope extending well nigh the full length of the 
viaduct, the work will thus be carried on till the desired end is attained, 
that being reached when the rail level is fully 150 feet above high water. 
Were I to state that these are the exact methods by which those 
parts of the bridge presently treated of will be erected, I should only be 
laying myself open to the ridicule of all experienced engineers, as it is 
a well-known fact that no undertaking of such magnitude is ever carried 
out to the letter of the plans originally decided upon. The foregoing are 
only presented as the results arrived at after full discussion by all con- 
cerned, and as the principles on which the full details will be wrought 
out as the work proceeds. Thus far all has gone well, no difficulty having 
arisen which can be said to have taxed the latent ability of either the 
engineers or contractors ; and judging the future from the past there is 
every reason to conclude that in the near future the successful erection 
and completion of the Forth Bridge will be a matter of history. . 
Electric Lighting at the Forth Bridge Works. 
By James N. SHooLsRED, B.A., M.Jnst.C.E. 
[A communication ordered by the General Committee to be printed in extenso 
among the Reports. ] 
ty the summer of 1883 the contractors for this most important engineer- 
ing work, Sir Thomas S. Tancred, Arrol, & Co., decided to make use of 
electricity in the illumination of the works required for the preparation 
and construction of this large undertaking. The author was by them 
entrusted with the preparation of the necessary plans, together with the 
supervision of the arrangements to enable the lighting by electricity to be 
thoroughly and suitably carried ont. 
For the construction of the bridge and the proper preparation of the 
large amount of steel which enters into it, very large workshops have 
_been erected at South Queensferry, where also are concentrated the 
principal offices, central stores, canteen, &c. A steep incline conveys the 
materials from the height on which the workshops stand down to the shore 
of the Firth; the lines of way being then continued on a broad wooden 
jetty, fifty feet in width, projecting into the Firth for about seven hundred 
yards, up to the Queensferry main piers, whence springs the sonthern- 
most of the two large spans of the bridge. 
The island of Inch Garvie, situate in mid-channel, with its group of 
workshops, offices, &c., necessary for the operations carried on at this 
isolated and exposed situation, forms the next spot requiring, at present, 
the use of the electric light. 
