8 
MINUTES OF PROCEEDINGS OF 
This board is covered with white paper on which the graduation, &c. is 
marked. From the point A a plummet is suspended by a fine silk line 
which is prevented from swinging from the face of the board by a guard ef. 
The graduation is from 0 to 15°, and along a line cd, perpendicular to that 
joining the point A with the zero mark, a couple of fine sights (or a small 
telescope with cross wires) are placed. 
The sector forming the actual clinometer is marked on the white face of 
the board. Its radius is 18 inches, and this size allows it to be graduated 
without difficulty to every 15 minutes. The sector is divided by a number 
of concentric circular arcs, as shown in the figure. In one of these divisions 
the ranges in yards corresponding to the degrees of depression are marked. 
In the next one the tangent scale elevations for round shot and shrapnel 
are given. In the next the elevation for common shell. In the next the 
length of fuze for ditto, &c. &e. All of these being legibly printed in the 
direction of the radii. Before they are finally inked in, their correctness is 
ascertained by actual practice. The ranges are of course found by dividing 
the height of the battery above the sea (in yards) by the sines of the angles 
of depression. 
The post, with its bucket and brass pin, is a fixture in the battery, but 
the block D and clinometer lift olf it, and are kept with the other gun stores. 
On the guns being prepared for action the clinometer is brought out and 
slipped on to the post. As it turns freely round G and also round the 
screw Hj when unclamped, the sights cd can be at once directed on any 
required object. The screw is. then clamped, and the range , elevation , Sfc. 8fc. 
read off on the radius the plumb line coincides with . I have found this 
instrument to answer perfectly. It gives the range of an object to a nicety, 
and even the dip of the horizon can be exactly ascertained by it. It is very 
simple in its construction, costs little, and can be made up by any carpenter. 
The most stupid man can use it, provided he knows how to read, since all 
he has to do is to turn the sights on the object and clamp the instrument, 
when the indicator tells him everything he wants to know. 
Of course if there be more than one nature of gun in the battery there 
will be more divisions required on the board, but in this case it would be 
easy to have a separate clinometer for each calibre. 
It is very difficult to hit ships in motion with any degree of certainty, but 
where this clinometer is used in batteries at any considerable height above 
the sea, the uncertainty will be reduced to a minimum, since the exact 
distance of a ship can be read off at any instant, and the proper amount of 
elevation called out at the same time. 
