202 THE LENSES OF BINOCULARS. 



right, will take care to see that his optician makes his 

 glass to fit his eyes, instead of trying to make his 

 eyes fit the maker's glasses. 



There remains the question of the material of which 

 the mountings of glasses should be made; the greatly 

 superior lightness of aluminium is incontestable, but it 

 is far less strong than brass, and the threads of the 

 screws in the softer metal are liable to be injured by 

 frequent use, or by any rough handling. Moreover, 

 apart from the much greater expense of aluminium, it 

 does not stand severe changes of climate as well as 

 its older rival, and at sea the salt water rapidly dete- 

 riorates the new metal, aluminium being to a certain 

 extent soluble in chloride of sodium. Whether there- 

 fore in a wild country, where all articles require to 

 be strong to withstand the constant knocking about 

 and the general wear and tear of hard service, a 

 traveller would' be well advised in adopting aluminium 

 in place of the more serviceable brass, is a matter 

 which we may well leave to our reader's intelligence, 

 with a view to his own particular tastes and require- 

 ments. 



In all hill shooting the glass is called into constant 

 requisition, and a good one of some kind is almost a 

 sine qua non, as on account of the rugged nature of 

 the ground game may at any time be within view, 

 among rocks or hollows, where it cannot be easily 

 seen; or may be lying concealed among bushes or 

 ferns, from whence they can see anything that ap- 

 proaches from the leeward side, and most game animals 

 make it a regular practice to lie down facing the wind, 

 with this intent. In consequence it becomes a matter 

 of high importance to approach the crest of any eminence 



