ABSTRACTS OF SCIENTIFIC PAPERS 359 



XIX. Lectures on the Maintenance of Efficiency of Telegraphic 

 Lines. Royal Engineers Institute, Chatham, 1863. 



XX. Cantor Lectures on Submarine Telegraphy, delivered before 

 the Royal Society of Arts (January to February 1866). ' Journal 

 cf the Society of Arts,' 1866 ; ' Reprints of Reports on Electrical 

 Standards,' p. 200. 



Lecture I. is on the insulated conductor and its properties, and 

 deals with the mechanical and electrical qualities of copper, gutta- 

 percha, india-rubber, and Hooper's material ; the question of perma- 

 nency and of absorption of water ; the manufacture of the core, and 

 its mechanical properties when completed. 



Lecture II., on shallow and deep water cables, describes the 

 serving and sheathing of the core, and treats of the strength of the 

 sheathing ; the mechanical properties of the completed cable ; the 

 maintenance of cables in shallow seas ; returns from cables ; statistics 

 of deep and shallow water cables ; and concludes with abstracts of a 

 number of specifications. 



Lecture III., on laying and repairing cables, gives an account of 

 the stowage on board ship, the use of tanks, the precautions against 

 fouling during the running out, the brakes and other paying-out 

 gear ; the theory of submersion, as sketched by Sir W. Thomson 

 and independently elaborated by Messrs. Brook and Longridge, with 

 applications of the theory ; the lifting and repairing of cables in 

 shallow and deep water. 



Lectures IV. and V., on electrical tests, define the terms used, 

 and describe the ordinary tests of the conductor and insulator during 

 and after manufacture ; the tests at sea ; the tests of short lengths by 

 the electrometer ; the tests of joints ; capacity tests ; tests for faults, 

 namely the loop test, for a cable in the factory or on board ship, and 

 the potential test for a submerged cable, both of which, although 

 first used by other electricians, had been independently devised by 

 the lecturer. 



XXI. Lectures on Electrical ^feasurements 1 delivered at the Royal 

 Engineer Establishment, Chatham (February 1867). Written 

 by Captain R. H. Stotherd, R.E., and revised by the lecturer. 



In these three lectures an account is given of the theory of 

 electrical units and the relation of electrical quantities to one another ; 

 the principles and practice of measurements of resistance, permanent 

 currents, transient currents, and currents of periodically varying 



