OPTICAL INSTRUMENTS. 



177 



Fig. 681. 



drawn out till the object is quite distinct, differ- 

 ent distances requiring a slight alteration in the 

 length. Piice, 1 draw, 50cts; 2 draws, 75cts ; 

 3 draws, $1.00. 



Fig. 682. 



Pocket Achromatic Telescopes. 

 (Fig. 681.) These telescopes are 

 mounted with mahogany body, 

 having an achromatic object glass, 

 and brass tubes, on sliders draw- 

 ing out three times. The eye 

 piece contains four lenses, and are 

 instruments of considerable power. 

 They are made of sizes from six- 

 teen to thirty inches in length 

 when drawn out, and from six to 

 ten inches when closed. 

 Price, 16-inch 3 -draw achromatic 

 telescope, $4 to $6. 



" 22-in. 3-draw " $6 to $8. 



" 30-in. " $10 to $.12 



Military Telescope. (Fig. 682.) 

 The military telescope is an in- 

 strument of the best construction 

 and made in the most portable 

 manner, having five to eight slides, 

 and folding up in a small compass ; 

 when used for military purposes is 

 inclosed in a leather case, having a 

 belt for suspending it over the 

 shoulder. They are made of va- 

 rious sizes, from fifteen to thirty- 

 eight inches in length when drawn 

 out, closing up to from four to ten 

 inches in length. 



Price, 15-in. 6-draw military tele- 

 scope, - - $7.50. 



" 20-in. 6-draw " $10. 



" 24-in. 6-draw " $20. 



" 38-in. 4-draw 



$15 and $20. 



