While the application of the telescope to the rifle is by no means a new idea, it is, however, more necessary in this age of high-power rifles, whose killing reng,es are beyond the accurate perception of the unaided vision. It is, there fore. obvious that the application of the telescope to arms of this type renders them at once serviceable to the extreme limit of their power. The universal employment of smokeless powder in ail guns of this sort has opened the way to the adaptation of the telescope to them. A great advantage gained in using the telescope in shooting is the elimination of the opaque or metallic for ward sight, which increases in apparent diameter as the distance between the marksman and the target increases, often more than covering the entire object at long ranges.
The principle of the rifle telescope is the same as that employed by the sur vey-or, who, through the medium of bis telescope, equipped as it is with delicate cross-hairs, is enabled to make accurate observations when sighting upon objects at great distances. To be of value, the telescope must be both water and dust proof and always in focus for any range; the field of vision large, flat and clearly :illuminated throughout; the cross-hairs must intersect one another at the exact center of the illuminated field and be sharply defined. The mount : .
:rigs securing it to the gun should be universally adjustable, and, so made that repeated firing with heavy charges will not jar the telescope, or in any wise alter its relationship with the bore of the gun, and yet lea\ e no parts protruding to catch the clothing or underbrush. The telescope must be so mounted upon the gun that it can be set quickly and easily for the required ranges and to compensate for errors due to wind.
The fact that these telescopes are practically- univers2.1 in Locus renders it possible for those who in a moderate degree are either near or far sig-hted to use them perfectly without the presence of glasses. Those after big game in ' the mountains or on tbe plains, where distances are great, will find the telescope invaluable in locating and killing it,: the wide, clear field allowing great range in sighting moving objects. The different varieties magnify from three and one-half to twenty diameters, and have such marked illumination that in feeble and uncertain light objects which would otherwise escape the notice are quite distinctly seen. Objects invisible to the naked eye after dusk are thus rendered clearly visible. For target shooting with the modern, high-power guns at long range, the stronger powers are most suitable, while for hunting, the lower ones are preferable.
The telescope mounted on the United States military rifle—the Krag-Jor gensen—does not consist solely of a corrected objective and a simple glass eye piece, but contains a thoroughly corrected achromatic objective and complete achromatic eyepiece as well, which features fully develop the optical properties of the glass and give to the telescope an exceptionally large, flat and fully illu minated field, together with a remarkable long focal relief. The lenses forming
the achromatic refracting systems are all made from the highest quality of optical glass, and so ground and arranged as to admit of no loss of light, thereby greatly increasing the illumination and definition. The non-breakable cross-hairs are placed exactly within the focus of the eye lens of the eyepiece and are dis tinctly seen under all conditions. All of the lenses are securely burnished into their cells, which are held in such a manner as to prevent the slightest movement from the sharpest recoil.
The Cataract Tool and Optical Company make three styles of mountings, two side and one center, all of which are adjustable, and arc desig,ned for holding thd telescope either directly' upon the top of the gun or on the left side, as re quired. The side mountings can be used on any style of rifle; the top or central mountings on single-shot. breech-loading rifles and those which eject on the side. When the side mounting is used, the open or Lyman si,g-hts need not be removed; but when the central mounting is used, other sights must be taken off. By the introduction of the bali and socket ring a reliable means for attaching the tel escope to the gun has been perfected. Heretofore various imperfect devices used for this purpose were a serious drawback to the employment of the telescope, in asmuch as none of them would admit of universal adjustment without cramping in some parts, and, as a result, the telescope would quickly alter its position with relation to the gun after firing a few times, no matter how tightly the binding screws might be set up. These mountings hold the telescope close to the gun, giving extreme rigidity and wide rang,e of adjustment, tog,ether with a compact and symmetrical appearance. In mounting the telescope on the top of barrel, the telescope is made to exceed the length of the gun barrel, irrespective of the power. Thus the forward end of the rifle does not obstruct the view when the telescope is raised for increased rang,es. On the top-ejecting and most repeating rifles the telescopes are mounted on left side of p-,un, and when thus mounted, any tube length may be used in keeping with power required, for in elevating- the tele scope for increased ranges the gun barrel does not. in this instance, come into view. Telescopes mounted in this way are morc compact, lighter and more easily adjusted, and admit of the use of regular sigdits also. Fig,ures t, 2 and 3 show the telescope mounted on the German Mauser sporting rifle, the Winchester maga zine rifle .4.3-9o, and Savage sporting- rifle, respectively. Figure 4 shows the rear mounting, designed for holding the telescope upon the side of the rifle as close as possible. It allows for elevation for increased ranges, by means of a micromter screw graduated to 1-600 of an inch. The front mounting allows for windage adjustment by means of the same form of micrometer screw graduated to 1-600 of an inch.