880 REPORT—1885. 
On the northern, or Fife, shore of the Firth, the operations about the 
Fife main piers, the northern end of the second of the large spans, together 
with the branch workshops, stores, &c., connected therewith, as well as 
portions of the land viaduct extending northwards, and a part of the large 
stone quarries and shipping stages in the vicinity thereof, are the spots. 
there requiring to be lighted by electricity. 
The conditions to be fulfilled in the illumination of the above localities 
(owing to the ever-changing extent of the demands upon the lighting and 
the alteration in the position of each light—a matter which varied con- 
stantly, with the progress of the work in its vicinity, with the state of 
the tide, and from other causes) rendered it evident that the details of 
the arrangements for the lighting must be such as to allow of the requi- 
site changes being effected readily and expeditiously. 
Again, it was seen also that portions of the cables, wires, and other 
working parts of the ighting apparatus would be constantly within reach. 
of the workmen. The primary condition, therefore, demanded a system 
of lighting simple in its arrangements, and which would inspire confidence 
in the new illuminant among the workmen. 
It became evident, also, that while arc lights would be required for the 
outside, the offices, residential premises, stores, &c., demanded incan- 
descent lights ; and, again, that other buildings, such as the large work-, 
shops, nesessitated the use of both are and incandescent lights. Likewise, 
that the use of storage accumulators, as well as the transmission of power’ 
by electricity, might at some time be desirable. 
To meet these various conditions it was decided: 1st, to adopt con-- 
tinuous current machines; 2nd, that the type of dynamo for the outside 
arc lights (limited to six lights in series) should not have a greater 
E.M.F. than 300 volts between the terminals; 3rd, that the type of 
dynamo for the incandescent lights, or for the arc and incandescent lights 
used conjointly, should be on the so-called ‘compound-wound ’ principle, 
with a maximum E. M. F. of 120 volts between the terminals. The 
incandescent lamps, in parallel series, used with these machines to have 
an K. M. F. of 110 volts; while in the large workshops arc lamps in pairs: 
(an series with one another, with the addition of a suitable resistance): 
would be used, where required, conjointly with the above incandescent 
lights. 
: Near to the large workshops are a number of parallel-lines of rails, 
forming a large uncovered workshop, and termed the ‘ drill-roads.’. Upon 
these roads circulate large moyable huts, each containing an engine, 
drilling machines, and a circular frame intended for the formation of the 
various steel tubes of the bridge. Here, as in the large workshops, the 
use of both are and incandescent lights is necessary. But, as the exact 
site where each kind of light might be wanted depended upon the where- 
abouts of the hut upon the rails, it became necessary to provide for this,. 
at certain fixed points, supply or ‘service’ boxes, whence readily fixed 
flexible branch-mains lead the current to the desired site of the lights. 
Tenders having beea invited for the carrying out of the necessary 
works, all the lighting on the South Queensferry side was entrusted to, 
and very efficiently carried out by, Messrs. Siemens Brothers & Co., 
Limited; while the works on the north side and on Inch Garvie were 
ee in a very satisfactory manner by Messrs. R. E. Crompton 
o. 
The electrical plant contained in the above installations may be stated: 
