Haddon and GrREEN — Secoud Report on Irish Marine Fauna. 49 
This wire is supplied in lengths of from 100 to 400 fathoms, with a 
tensile strength of from 200 to 240 lbs. Great care is required in 
making the splices, which are always a source of weakness, and not 
being galvanized, the reel, when not in use, has to be immersed in a 
tank of lime water or oil to preserve the wire from rust. 
"Wishing to avoid the trouble and danger of splices in the wire, and 
also the carefulness required to preserve it from corrosion, I entered 
into corespondence with Messrs. B,. S. ITewall & Co., Gateshead-upon- 
Tyne, and they were able to supply me with two pieces of galvanized 
steel wire, 22 Birmingham wire gauge — one piece of 1400 fathoms, and 
the other of 1300 fathoms. This wire had a breaking strain of 260 lbs. ; 
we had no need of splices. One piece only has been used ; and though 
it met with various sharp nips from slight accidents in working, and 
although it was subject to very severe strain when it was being reeled 
in by steam while our vessel was going full speed ahead, it seems quite 
uninjured.* The greatest depth to which we sounded was 1100 fathoms. 
Between the lead and wire was a stray line of stout cord, 10 fathoms 
in length. This was necessary in order to avoid the risk of the wire 
reaching the bottom, where it would get kinked and then break, and 
to this stray line a thermometer was occasionally attached. 
Our spare piece of wire was coiled on a duplicate reel, which was 
ready to slip on to the axle in the place of the other in case of an 
accident. 
The register on the axle of the sounding-reel did not, of course, 
record fathoms, it merely recorded revolutions ; and the length of wire 
represented by one revolution varied in proportion to the amount of 
wire on the reel. In order to discover the depth, it was necessary to 
construct a scale, reducing revolutions to fathoms : the scale was after- 
wards converted into a diagram with curve. 
In all this portion of the preliminary work I have to thank Mr. T. 
H. Poole, C.E., for the great assistance he rendered. 
The plan we adopted in constructing the scale was as follows : — 
The sounding machine with reel empty was set up in position with 
register on axle at zero. On a turn-table, a little distance away, the 
coil of wire was placed ; between these a wheel, one fathom in circum- 
ference, was set up. This wheel was also provided with a register 
which started at zero ; 50 fathoms of wire were then carefully measured 
against an even wall, then passed over the fathom-wheel, and wound 
2 The same wire was used again this year (1887) for sounding and temperature 
observations in Dublin Bay, and is as good as ever. 
B. I. A. PEOC, SEE. III., VOL. I. E 
