18 DEER-STALKING. 



of glass. It is on sheep ground that the glass with the 

 large field is of the greatest service ground which may 

 have been spied for four or five days in succession 

 without seeing a sign of a deer, but which on the sixth 

 may hold three or four stags, or perhaps a solitary one, 

 which might easily be passed over with a glass having 

 a small field by shifting it too quickly and missing the 

 very spot where the deer are. 



When putting a telescope away at the end of the 

 season be careful to choose a perfectly dry place. If 

 a glass be laid by in damp for any length of time, the 

 oxygen of the air actually corrodes the lenses, and gives 

 them an opalesque coating which can only be removed 

 by repolishing; and although such a mishap does not 

 render the glass totally unfit for use, it spoils the sharp- 

 ness of the definition and dims it to a great extent. 



