944 REPORT-—1890, 
fired from one of her 68-ton guns in 9 minutes 5 seconds. In the Colossus, when 
under command of Captain Cyprian Bridge, the average from one round to 
another was 1 minute 45 seconds, and on one occasion, steaming at 8 knots per 
hour past a target at a distance of 1,500 yards, she fired four rounds in six 
minutes, striking the target three times. 
Of the mountings which are worked solely by manual power, the whole range 
for naval service is covered by the carriages of the type designed by Mr. Vavasseur. 
No single description can be made to cover all the varieties of these mountings. 
which have been worked out to meet the diverse conditions which have arisen in 
the re-arming of old ships, and the fitting out of new vessels on modern and novel 
designs, The very general adoption of breechloading ordnance brought with it the 
necessity for a mounting which would give easier access to the breech of the gun 
than was obtained with the long low gun-slide employed with the muzzle-loading 
guns. The main features of the type therefore are, a hich slide, very short, so as 
not to project beyond the breech of the gun, a short low carriage carrying on either 
side the recoil presses, and a shield to afford protection both to the carriage and the 
gun crew. 
The increased importance of rapid-fire guns has led in later carriages to a strong 
armour plate being built into the mounting as part of its structure, and to this 
must be added the shield above mentioned, so that the total protective thickness of 
plate is very considerable, 
By means of a worm wheel sliding on a keyed shaft the movement of the gun. 
for elevation or depression can be made up to the instant of firing—a decided and 
very important advance on the older methods. 
The arrangement of the recoil-cylinders is peculiar. They are fitted with a pair 
of pistons with rotating valves, so adjusted as to be open when the gun is in the 
firing position, and to be gradually closed during recoil by studs running along 
rifled grooves in the cylinders ; by this ingenious contrivance the area of the ports 
of the valves is increased and then decreased in proportion to the variation of the 
velocity of recoil, so that the liquid passes from one side of the piston to the other 
at as nearly as possible a constant velocity and under a constant pressure. The 
velocity of the flow through the ports, and therefore the pressure of the liquid, 
varies with the energy of the recoil of the gun, so that the length of the recoil is 
with all charges practically the same. 
Even a blank charge produces nearly full recoil, and on one occasion caused one 
of these mountings to be reported as unserviceable, and unfit to fire a shotted 
round. Constant length of recoil has the advantage over constant pressure in the 
recoil-presses that, in the event of an unusually heavy recoil, a higher pressure 
in the recoil-press would in the former case be the only result, and would do no. 
harm, as the pressure would still be much below the test-pressure ; but in the latter 
case there would be an increased length of recoil, and, unless considerable margin 
were allowed, a possible destruction of the slide. 
Most frequently the Vavasseur mountings are made with central pivots, and 
there is then little tendency for the movements of the vessel to affect the mount- 
ing, and as the weight is borne upon a ring of live rollers the greatest ease of train 
ing is obtained. 
In the larger sizes the centre pivot is increased in size, and made hollow so as 
to provide for the passage through the centres of a powder hoist, which, after rising 
high enough, curves to the rear under the gun and delivers its charge at the point. 
where it can most conveniently be drawn out for insertion in the gun. In this 
case a foot plate is also provided as a rear attachment to the slide, and from this 
the crew work the gun. This foot plate is provided with boxes for eight or ten 
projectiles, which are therefore ready for use at any moment and in any position of 
training. These mountings are fitted in the belted cruisers of the Orlando class, 
one being carried at the fore and one at the after end of each ship. 
As a sufficient proof of the value of these mountings and of the ability which 
has been displayed in their design, I may mention that practically all countries. 
have adopted these carriages for modern guns, either without any alteration or 
with comparatively unimportant modification. 
