—— 
On a new System of Defence by vertical Firing. 177. 
hot be pointed so as to touch him, on account of his closeness 
to the rampart. In order therefore to annoy the enemy in that 
position, Mr. Carnot invented a new system of attacking | him 
there by what he calls Vertical Firing, which has obtained great 
applause by engineers on the continent of Europe. This method 
is described as a mode of diecheseNnD) a multitude of small balls 
from cannon pointed upwards, nearly in the vertical direction, 
so that the balls, after ascending to their utmost height, may 
fail down again like a shower of hail, on the heads and shoulders 
of the men in the ditch. It seems that those engineers imagined 
that these showers of balls, in their descent, ial fall to the 
ground with a velocity or force equal to that with which they 
were discharged from the cannon, and that as the latter is ca- 
pable of destroying men, the former must likewise have the same 
effect. , 
But this it appears is a very vain and fallacious opinion, as, 
owing to the enormous resistance of the air to bodies moving 
with great velocity, being indeed even more than in proportion 
to the square of the velocity, the utmost velocity of the descend- 
ing balls is comparatively very small and har mless. This cir- 
eumstance is fully demonstrated in Dr. Hutton’s artillery experi- 
ments, as well as many others, in the 2d and 3d volumes of his 
Tracts, where rules are delivered to assign the utmost velocity 
that can be acquired by bodies, of any size and weight, falling 
through the air from any height whatever, and therefore called 
the Terminal Velocity. 1n particular, by consulting the table of 
such velocities, in page 247 of the 3d volume above mentioned, 
it will appear that such balls cannot acquire a velocity, by de-, 
scending, of so much as 200 feet per second of time, even if they 
were discharged upwards with ten times as much. 
This grand, this fatal mistake of the continental engineers, 
having been observed by Sir Howard Douglas, Bart. one of the 
many able engineers educated by Dr. Hutton, at the Royal Mi- 
litary Academy at Woolwich, lately Inspector General of the Royal 
Military College, and now Inspector of the Hon. East India 
Company’s Military Institution at Addiscombe near Croydon, he 
lately published a work, entitled ‘¢ Observations on the Motives, 
Errors, and Tendency, ‘of Mr. Carnot’s Principles of Defence,’’ 
&c. meant to expose and correct the error of that system, and 
prevent the fatal consequences that were likely to attend it ; and 
which it seems is now in a fair way of being completely effecte ed, 
as appears by the following letter just received by Dr. Hutton, 
from that gentleman, who is now with his family at Caen in 
Normantly ; 
Vol. 58. No. 281. Sep. 1821. Z “To 
