320 
MINUTES OE PROCEEDINGS OE 
by its .capability of reversing ; and by its power of passing obstacles. 
To render, therefore, a carriage mobile, " the draught must be as light 
as possible.” This necessitates, in the first place, the? load being a 
minimum—that is, the weight of the gun, or ammunition, &c., to be 
carried being given, the weight of the carriage a minimum—and in the 
second place, that the load be properly distributed over the axles. 
Before passing on to the other points which affect the draught, it is 
to be noticed that the distribution of the load depends upon the relative • 
diameters of the fore and hind wheels, and upon the fact that the 
traction of the fore carriage, taken by itself, is usually more difficult 
than that of the bind; because the fore wheels make, as it were, the 
tracks, and in so doing reduce the height of any obstacles for the hind. 
These considerations point to the reduction of the load upon the fore 
axle as compared with that on the hind; but, on the other hand, the 
fact must not be lost sight of, that if too much weight be thrown on 
the hind axle relatively to the fore, it will cause the hind wheels to 
sink too much in yielding ground, and thereby (though the decrease 
of weight on the fore axle tends, as before, to lighten it) to increase the 
draught on the whole. 
Again, for lightness of draught, the axles must be of such length as 
to give the same track to both fore and hind wheels; in order that, as 
above, the fore may, in doing their own work, also assist the hind. 
The diameter of the wheels must also be a maximum, and that of the 
axletree a minimum. With regard to the former, the diameter of 5 ft. 
has been fixed upon as that most suitable for the field wheel. 
Lastly, that the draught may be light, the point of the attachment 
of the traces must be the most favourable—that is, as regards height 
from the ground; it must be such as to give the most advantageous 
inclination to the traces. The point of attachment to the horse—-viz., 
the collar—being fixed, experience has shown that this inclination 
should be about 6J°. 
The carriage, to be mobile, must, in addition to being light in draught, 
be “ capable of wheeling, or reversing, very short • ” that is, not only 
must the carriage be of a minimum length, but the angler through 
which the fore carriage can sweep must be as large as possible—which 
latter mainly depends upon the diameter of the fore wheels, and details 
of construction of the body of the carriage. 
The mobility of the carriage is influenced by what may be called its 
“ power of passing obstacles,” which point, so far as the wheels and 
inclination of the traces are concerned, may be considered as included 
under “ lightness of draught; ” but beyond this, is influenced by the 
mode of connection of the fore and hind carriage, which should be 
such as to admit of vertical motion of the fore carriage about the point 
of connection, so- that the fore carriage may move in that direction 
independent, to some extent, of the hind carriage. The distance 
between the axles also slightly affects the power of the carriage to 
pass obstacles, but need hardly be taken into account, as the length 
between the axles best suited for passing certain obstacles will not be 
the best for passing others. And here it may be as we]l to remark, 
with regard to the distance between the axles, that it does not in 
