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MINUTES OF PROCEEDINGS OF 
level ground platform to start with lias the advantage of keeping the wheels 
of the carriage on the same plane, however much the trail maybe inclined to 
the axis of the platform. 
In the “ curved fire” from “A” battery, the line was accurately found by 
using the sling-scales, slightly modified from the Prussian. They consist 
simply of two metal bars, graduated alike in plain figures, and horizontally 
suspended by steel rods with hooks—one beneath the axletree, and the other 
about half-way down, and underneath the trail. An axis-line is clearly 
marked down the centre of the platform—or three parallel lines to save 
traversing the carriage—which axis-line has been laid carefully by pickets, or 
other means, upon the object to be fired at. As both scales are alike, it is 
evident that when they are properly adjusted upon the carriage we get the 
gun correctly laid by bringing any two similar graduations exactly over the 
line marked on the platform. The Germans give deflection by bringing a 
different figure on the rear scale to correspond on the axis-line with one on 
the front scale; but the scales in question possess a great simplification in 
having a small separate graduation on the right of the rear scale, by means 
of which any required deflection can be given by sliding the scale in its 
slings, which have clamping screws. We are thus enabled always to adjust 
the same figures on both scales to the axis-line—a decided advantage for 
rough and ready work in the trenches. 
January, 1875. 
