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A NEW COLLIMATING-TELESCOPE GUN-SIGHT FOR LARGE AND SMALL 

 ORDNANCE. By SIR HOWARD GRUBB, F.R.S., Vice-President, Royal 

 Dublin Society. 



(Plate XXVI.) 

 [Read, Mahch 20tli, 1901.] 



When it is necessary to point any instrument at an object, whether it be a rifle, or 

 a gun, f)r a telescope, it is usual to do so by glancing at the object along the axis 

 of the instrument, or some member or part which is parallel to the axis, bringing 

 this part as nearly as possible into the line of sight between the eye and the 

 object aimed at. This is done instinctively, without any education or instruc- 

 tion, and it is curious to note that in this, the twentieth century, the most 

 primitive and unscientific method still endures, and is used in all but exceptional 

 cases for sigliting purposes in our most modern weapons. 



It is true, of coui'se, that for the more delicate operations involved in 

 geodetical surveying, and in astronomical work where greater accuracy is a 

 necessity, the telescope is used to determine the bearing or direction of objects, 

 and of late years, the same has been applied to the directing of some of our 

 larger ordnance ; still the fact remains, that notwithstanding the ingenious and 

 sometimes complicated refinements applied to guns of various types for the 

 elimination of errors due to the trajectory, drift, windage, &c., the ultimate 

 sighting, or laying of the gun in that particular direction which will cause the 

 projectile to hit the target, is effected by this same primitive method, wliich, 

 though capable of giving wonderfully good results in the hands of highly skilled 

 and exjDerienced marksmen, is hardly adequate for modern requirements. 



Even the most cursory student in such matters cannot fail to have noticed 

 tliat, as a result of the labours of successive generations of military and mechanical 

 engineers and scientific men, modern weapons of war have been developed to an 

 extent beyond all expectations, and yet, notwithstanding all these improvements, 

 the survival of all that is good from the vast labour that has been expended on 

 the subject, the ultimate operation of laying the sights of a modern gun is the 

 same in principle and in effect as that used with the weapons of mediaeval 

 ages. 



TRANS. ROT. DUB. SOC, N.S. VOf, VII., PART X. 2y 



