484 
MINUTES OF PROCEEDINGS OF 
The multiplying alidade affords the means of recording the position 
of every shot as it falls on the water around the target in succession, 
with the utmost precision and expedition, so as to obviate the possi¬ 
bility of the mistakes and inaccuracy which must prevail in the absence 
of this or some similar instrument of measurement. 
The alidade, as at present constructed, consists of two telescopes, 
quadrant, eye-piece, diaphragm, hood, and cross wires, mounted on a 
superior radial arm AA , 6 ft. long, connected with and acted on by an * 
inferior radial arm BB, pivoting at any distance, as may be adjusted, for 
recording the practice upon the register according to any convenient 
scale that may be required by the range. 
The record is made on a register of one or more thicknesses or sheets 
of paper, by means of perforation by a steel point, acted on by a 
spring and trigger attached to the index of the inferior radial arm. 
The register is stretched on a table, mounted on a traversing bed i), 
acted on by a guide screw F, advancing the register at regular intervals 
for receiving the successive observations. 
The observations taken under the cross wires at the extremity of the 
superior radial arm are thus brought back to the hand of the observer 
at the recording apparatus attached to the inferior radial arm, with a 
power of angular measurement which may be multiplied or reduced 
by the position of the pivot C, the inferior radial arm, to suit the 
nature and range of the observation. 
When practice is about to commence, the alidade, secured to a gun 
or other support, is to be carefully aligned upon the target, the index 
being secured at zero. The back sight and cross wires being then in 
collimation with the target, the eye-piece and cross wires of the telescope 
will also be found in collimation ; if not, the necessary adjustment is also 
to be made. The line of collimation being now marked on the register, 
the index liberated, and the hammer raised, the instrument is ready to 
register the position of the first shot as it falls. 
This operation is effected by bringing the falling shot or bursting 
shell under the cross wires, by moving the alidade index to the right or 
left, and spotting the position on the register by touching the trigger* 
thus marking the position of the shot in or out of the line of collimation 
above referred to. For the second shot, nothing further is required than 
to raise the hammer as before, advance the register one-tenth of an inch 
by one turn of the guide screw, spotting the second shot, and so on to 
the end of the practice. 
The second telescope, mounted with the quadrant, is required when 
the instrument is to be employed as a range-finder. 
There being at present no system of prize competition with heavy guns 
established for the practice of the Eoyal Artillery, the necessity with 
which I have been familiar for the last ten or eleven years, for an 
accurate and reliable test of the relative value of the practice of com¬ 
peting detachments and gunners will not be so apparent; but if we con¬ 
sider the admirable materials of the Eoyal Artillery, both in guns and 
gunners, the importance of any system leading to the improvement and 
accuracy of practice is so apparent that an attempt promising in any 
degree to aid in its development will sufficiently commend itself for 
examination. 
