92 PHOTOGRAPHY FOR BIRD-LOVERS. 



need mention, but, well remembering the nature 

 of the rope we were foolhardy enough to use when 

 beginning, and bearing in mind the number of 

 Alpine accidents due to breaking ropes, a word 

 of advice on this point may not be unnecessary. 

 If, at the time of purchase, it were only fully 

 realized that when working in the great cliffs a 

 broken rope means death, it is more than likely 

 that the article acquired would not err in the 

 direction of insufficient strength, but rather, 

 perhaps, in that of undue weight, which, though 

 not of the same vital importance, is a drawback 

 rigorously to be avoided. 



The Ropes. 



The ideal rope is the very lightest, compatible 

 with the required strength, and in estimating the 

 necessary strength there are several factors to be 

 taken into consideration. The rope has not simply 

 to support a dead weight of so many stones, nor 

 only the same as a live load ; it must be able to 

 withstand the strain caused by one's body falling 

 through many feet (occasioned by a slip when the 

 rope is slack) and the terrible jerk ensuing when 

 the rope pulls taut ; and further, it must be of such 

 ample strength as to fulfil these requirements 

 after it has been much chafed by the sharp edges 

 of the rocks. A factor of safety of ten to fifteen 



