,814 REPORT — 1888. 



upon an extension of the work. The tension of the current employed is never high 

 ■enough to endanger life or property ; while the consumer has a reserve of elec- 

 tricity always at command, and is thus relieved from all anxiety regarding any 

 :fiudden failure of the supply. 



5. The Measurement of Electricity in a House to House Supply.^ 



By W. LowRiE. 



6. Electric Light applied to Night Navigation upon the Suez Canal.'^ 

 By R. Peect Sellon. 



I. Duriuo- the commercial crisis extending from 1878 to the early years of the 

 present decade, traffic upon the Suez Canal increased largely. The number of ships 

 -passing through the Canal in 1878 was 1,593; this increased to 3,624 vessels in 



1885, equal to a gross tonnage of nine million tons. 



Increased traffic gave rise to inconveniences and resulted in frequent delays. 

 Shipowners put pressure upon the Canal Company to afford facilities to cope with the 

 increased traffic. In 1885 the average time occupied in passing through the Canal 

 (eighty-seven geographical miles long) amounted to from forty to forty-five hours. 

 "To meet the general demand the Canal Company introduced various improve- 

 ments and in the year 1884 commenced experiments to determine the jjracticability 

 of navigation during the night by means of the Electric Light. 



Owfng to difficulties incident to the case these experiments occupied two years, 

 'resulting in an authorisation issuing from the Canal Company, in December 1885, 

 permittino- vessels of war and mail boats to navigate some portion of the Canal if 

 provided with suitable Electric Lights. 



In April 1 886, the s.s. ' Carthage,' of the Peninsular and Oriental Steam Naviga- 

 tion Company, for the first time made the prescribed passage by night successfully, 

 and was followed shortly by others. 



The success of these results encouraged the Canal Company to extend the au- 

 thorisation to vessels of all classes, and to throw open the whole length of the Canal 

 to them. Thus, in February 1887, this authorisation was made public subject to 

 -certain regulations laid down by the (Janal Company. 



II. The plant to comply with above regulations consists of three essential 



3)arts : 



1. Dynamo-Generator and engine. 



2. Projector Search-Light to throw a beam 1,200 metres ahead of the 



vessel. 



3. Automatic Electric Lamp capable of illuminating a circular area of 200 



anetres diameter around the vessel. 



Accompanying diagrams illustrate the above plant and a vessel so fitted navi- 



•gating the Canal. . 



The engine is of Brotherhood's three-cylinder type coupled direct to a Brush 

 Victoria dynamo. The Projector Search-Light, fitted with spherical silvered 

 mdrror and diverging lens, is arranged to throw a beam diverging to angle of 

 twenty degrees to a distance of 1,200 metres. The projector is fitted to a platform 

 .arrano'ed to accommodate an attendant to manipulate the light, the whole being 

 fixed to the stem of the vessel, forward and close to the water-line. 



The automatic lamp is suspended from the masthead and lighted when passing 



III. Figures are adduced to show the development of the Electric Liirht for this 

 purpose: its advantages, economy, and probable future development are discussed. 



' Printed in extemo in Electrical Review, vol. xxiii. p. 308. 

 2 lUd. vol. xxiii. p. 279. 



