458 
MINUTES OF PROCEEDINGS OF 
base against three curved shields, each placed in the same relative position 
to one of the three vents, vide Tig. 1. 
The "object being to allow the gas to escape directly to the rear and so 
give its full available force to propel the rocket, the rotation being given 
by the gas in its further expansion after its escape from the rocket's base, 
which presses on the three shields. This method of utilizing work pre¬ 
viously wasted being somewhat analogous to the expansive working of a 
steam engine. 
N.B.—The above explanation is pretty, but it is not the exact truth to 
say that the force employed is not available for propulsion. 
The bore of each vent and the inside of its shield is part of a cone whose 
apex is to the rear, this form being taken from the “ turbine " water wheel, 
which is employed to obtain a very high velocity of rotation from water 
passing through similar orifices and striking the inclined surfaces; here 
there is no expansion, an extraordinary speed of rotation being given by the 
slight obstruction of the passage of the water. In the rocket the expansion 
of the gas increases the pressure enormously, but the question of retardation 
still holds good, and must necessitate a stronger, heavier rocket case in 
which a smaller vent might have been made, and any pressure on the rocket 
which gives the rotation might have been employed to give propulsion. 
This construction of Hale's gives good results. 
Machine . The rocket machine is a small one shewn in centre of sketch, 
length of tube 3 ft. 5 in., it requires little explanation. 
The tube hinges at the rear, and is fixed by a screw to such part of the 
vertical bar in front as gives the required elevation by the tangent scale. 
Above 7° good results are obtained. 
A friction tube resembling the one for the gun, but made up to fit the 
rocket's vent by paper wound round it, is used with a lanyard to fire the 
rocket with a quick pull, a slow one being liable to capsize the machine. 
Saddles . 
This subject is one requiring special experience to handle properly, a 
very few remarks are offered. It seems desirable, 
(1) That the saddle should rest fairly and evenly on the parts of the ribs 
which are most nearly horizontal, that is, the parts near the spine. 
(2) That the centre of gravity of the load should be as low as is 
convenient, and that the load should project as little to each side as possible. 
(3) That the girthing and lashing of load should be simple, strong, and 
easily tightened. 
