Along the British Pacific Cable. 



309 



Immediately upon completion — Oct. 31, 1902 — of the 

 British Pacific Cable, Canada made preparations to extend her 

 longitude determinations, which had been carried from Green- 

 wich to Vancouver across the Pacific, thereby making with 

 the longitude carried eastward via. Madras, a continuous 

 longitude circuit round the world. The writer was placed in 

 charge of the work and with him was associated Mr. F. W. O. 

 Werry, B. A. Each observer was provided with similar astrono- 

 mic outfits, and at each station occupied, a brick or cement 

 pier was built and a small observatory erected. Mr. Werry 

 occupied Fanning and Norfolk inlands, and the writer Van- 

 couver; Suva, Fiji; Southport, Brisbane and Sydney, Australia ; 

 Doubtless Bay and Wellington, New Zealand. 



Every night during the campaign the observers compared 

 their clocks over the cable. The comparison was made with 

 an accuracy of two thousandths of a second. By this com- 

 parison is measured too the time it takes for a signal to travel 

 over the cable. This of course varies with the distance. On 

 the longest section, over four thousand statute miles, it took 

 thirty-lour hundredths of a second, or say a third of a second 

 from the minute a clock ticked at one end, until it recorded in 

 ink that tick at the other end. The following table is self- 

 explanatory. 



Section. 



Length 



of cable 



laid. 



Naut. 



miles. 



Pounds of 



copper 

 and gutta 

 perchaper 

 naut. mile 



Electro- 

 motive 

 force . 

 Volts. 



Resist- 

 ance per 



naut. 



mile. 

 Ohmes 



Trans- 

 missions 

 Sec. 

 Time. 



Rate per 

 second. 

 Statute 

 miles. 



Bamfield — Fanning 

 Fanning — Suva 

 Suva — Norfolk 

 Norfolk — Southport 

 Norfolk — Doubtless Bay 



3457.8 



2043.1 



981.5 



836.7 



518.7 



600 ) 

 340 \ 

 220 i 

 180 \ 

 130 

 130 \ 

 130 ( 

 130 f 

 130 \ 

 130 f 



50 

 55 

 30 

 30 

 10 



2.03 

 5.54 

 9.35 

 9.35 

 9.35 



!3422 



.2807 

 .1404 

 .1016 

 .0528 



11.600 

 8.400 

 S.OOO 

 9.800 



11.300 



The comparison of the clocks combined with the clock 

 correction determined by each observer from tourist observa- 

 tions on stars, gives the difference of longitude between the 



