PROCEEDINGS 
OP THE 
ROYAL SOCIETY OF EDINBURGH. 
VOL. V. 1865-66. No. 69. 
Monday, ISth December 1865. 
Sir DAVID BEEWSTER, President, in the Chair. ' 
At the request of the Council, Professor William Thomson 
of Glasgow delivered the following Address on the Forces 
concerned in the Laying and Lifting of Deep-Sea Cables. 
The forces concerned in the laying and lifting of deep submarine 
cables attracted much public attention in the years 1857-58. 
An experimental trip to the Bay of Biscay in May 1858, proved 
the possibility, not only of safely laying such a rope as the old 
Atlantic cable in very deep water, but of lifting it from the bottom 
without fracture. The speaker bad witnessed the almost incredible 
feat of lifting up a considerable length of that slight and seemingly 
fragile thread from a depth of nearly 2^ nautical miles.* The 
cable had actually brought with it safely to the surface, from the 
bottom, a splice with a large weighted frame attached to it, to 
prevent untwisting between the two ships, from which two portions 
of cable with opposite twists had been laid. The actual laying of 
the cable a few months later, from mid ocean to Valencia on 
^ Throughout the following statements, the word mile will be used to de- 
note (not that most meaningless of modern measures, the British statute 
mile) hut the nautical mile, or the length of a minute of latitude, in mean 
latitudes, which is 6073 feet. For approximate statements, rough estimates, 
&c., it may be taken as 6000 feet, or 1000 fathoms. 
3 T 
VOL. V. 
