r. GEOGRAPHY. 235 



thinks is not any where within the peninsula between the 

 gulfs of Suez and Akaba, but in the Arabian Desert, east of 

 the head of the latter gulf. The whole amount needed for 

 the purpose is 500 sterling, and a considerable portion of 

 this has been already contributed, or promised on condition 

 of the completion of the whole. 13 A,October 1, 1873, 380. 



SOUNDING-LINES OF THE CHALLENGER EXPEDITION. 



As a matter of interest in relation to deep-sea explorations, 

 we learn that the sounding-lines used by the Challenger have 

 proved to be extremely efficient indeed, far superior to those 

 previously employed for the purpose. These are composed 

 of the best Italian hemp, which, when made up, has but few 

 protruding ends of fibres, and these are well rubbed down 

 with bees-wax and sweet-oil in equal proportions. The ad- 

 vantage of this preparation may be seen from the fact that 

 there is a difference of seventeen to twenty per cent, in the 

 time of going down in favor of those which are so treated. 



The number of threads also is somewhat greater. Thus 

 the ordinary deep-sea line heretofore used by the London 

 Admiralty has about eighteen threads, and weighs twenty- 

 three pounds fourteen ounces to the hundred fathoms, with a 

 circumference of 1.065 of an inch, the breaking strain being 

 630 pounds." The new line has twenty-seven threads, with a 

 weight of eighteen pounds nine ounces per hundred fathoms, 

 with a circumference of one inch, and a breaking strain, when 

 wet, of 1559 pounds. The new medium line of eighteen 

 threads weighs twelve pounds eight ounces to the hundred 

 fathoms, with a circumference of 0.8 of an inch, and has a 

 breaking strain, when wet, of 1211 pounds. 



The new cod line, weighing six pounds four ounces per 

 hundred fathoms, has a breaking strain of 777 pounds instead 

 of 252 pounds, as in the ordinary line. Thus with a decrease 

 of fifteen per cent, in weight of material used, an increase of 

 strength has been gained of between 100 and 200 per cent. 

 6 A, October 1873, 271. 



CANADIAN EXPLORATIONS. 



In noticing the great activity of the United States, in the 

 last few years, in the exploration of the regions of the West 

 and Northwest, we must not forget that Canada has been 



