26 
a0 
THE DEPTHS OF THE SEA. [CHAP. I. 
Dr. Wallich’s is the only book which discusses fully 
and systematically the various questions bearing 
upon the biological relations of the sea-bed, and his 
conclusions are in the main correct. 
In the autumn of the year 1860 Mr. Fleeming 
Jenkin, C.E., now Professor of Engineering in the 
University of Edinburgh, was employed by the 
Mediterranean Telegraph Company to repair their 
cable between Sardinia and Bona on the coast of 
Africa, and on January 15, 1861, he gave an interest- 
ing account of his proceedings at a meeting of the 
Institution of Civil Engineers.’ 
This cable was laid in the. year 1857. In 1858 it 
became necessary to repair it, and a length of about 
30 miles was picked up and successfully replaced. 
In the summer of 1860 the cable completely failed. 
On taking it up in comparatively shallow water on 
the African shore, the cable was found covered with 
marine animals, greatly corroded, and injured appa- 
rently by the trawling operations in an extensive 
coral fishery through which it unfortunately passed. 
It was broken through in 70 fathoms water a few - 
miles from Bona. The sea-end was however recovered, 
and it was found that the cable which thence traversed 
a wide valley nearly 2,000 fathoms in maximum 
depth, was perfect to within about 40 miles of Sar- 
dinia. It was then picked up from the Sardinian end, 
and the first 39 miles were as sound as when it was 
first laid down. At this distance from the shore there 
was a change in the nature of the bottom, evidenced 
by the different colour of the mud, and the wires were 
1 Minutes of Proceedings of the Institution of Civil Engineers, 
with Abstracts of the Discussions. Vol. xx. p. 81. London, 1861. 
