THE ROYAL ARTILLERY INSTITUTION. 
201 
Non-Essential Parts. 
The eye-pieces do not affect the adjustment; it has been already 
explained, under the head of object glasses, how any damages to these 
should be repaired. 
White Discs of Payer. 
In replacing these, care should be taken that the centre of the lower 
portion of the disc corresponds with the notch marked on the case. 
Tangent Screw. 
The only real damage that can happen to this is, that it may become 
stiff; this will be owing to a grain of sand having got into the bearing 
and scratched it; in this case the screw should be taken off and the 
bearing filed smooth. 
Roller. 
New rollers are liable to work very stiffly from moisture in the atmos¬ 
phere. In this case the rings should be taken off and their inner circum¬ 
ference, or the corresponding outer surface of the roller, scraped with a 
pen-knife, until the rings turn smoothly. 
Tape. 
This is the only perishable portion of the instruments. It is more 
economical to throw all the work on one tape, and to keep the others 
sound. 
The figures on the tape will have to be renewed in the battery every 
six months; the collar-makers will 1 also have to piece the tape up neatly 
now and then. 
The screws used in the range-finders are all of the Whitworth taps. 
Influence of the Range-Finder on Tactics. 
No general would, or probably should, modify his tactics for any im¬ 
provement in weapons without being thoroughly convinced that such 
an improvement was real; in the case of the range-finder a general 
should carefully examine for himself (before in the slightest degree he 
built his combinations on the change) if the superiority claimed for it 
is substantially correct. 
The superiority claimed is an average advantage of 3 to 1 in the 
destructive effect at ordinary artillery ranges, say from 1,300 to 2,000 
yards ; and a still higher ratio at long ranges, say from 2,00,0 to 3,500. 
To satisfy himself, the general will simply have to pit one battery, firing 
by trial shots at targets, against another firing with the aid of the range¬ 
finder ; the only precaution he need take is to see that those using trial 
shots work fairly, as there will be an universal desire on the part of 
the officers and men to supplement the trial shots by various dodges 
which could not be used on service. 
Starting, then, from the assumption that this superiority is real, but 
fully acknowledging that a commander should verify such assumption 
by his own individual experience, the modifications which may be thus 
introduced into tactics will be briefly weighed. 
