Lazare Carnot's "Vertical Fire" and the Wanting Rain of Death (1820)

 

JF Ptak Science Books   Post 2571    

Lazare Carnot (1753-1823) is a justifiably revered and famous person in the history of science and engineering, though not I think for the paper that I stumbled upon in a volume of The Quarterly Journal of Science, Literature, and the Arts¹ for 1820.  The article "Theory of Defence by Vertical Fire" (pp 200-295) sounded mysterious at first, though it was quickly revealed that the "vertical fire" related to the extreme angle for firing canons and mortars and such and not to a burning fire. This vertical firing of projectiles was reserved for opposing siege force of a fortification, fired at an angle so extreme that given the height of the charge and the extreme closeness of the enemy that it would seem to be raining bullets and shells upon them. Given that the opposing force would be entrenched and largely impervious to a more "horizontal" line of fire, the metal rain seems a consideration. Carnot described this as  an "impregnable" defensive position. Others saw it differently:  

"M Carnot boldly and ingeniously proclaimed the discovery of a new mode of defence by which fortresses might be rendered absolutely impregnable and by means so simple as to be easily adapted to all places. In promulgating this new doctrine Carnot introduced some useful materials and observations calculated to excite protracted defence but his general reasoning is quite delusive. He wrote as a political engineer or rather he compiled the treatise which he informs us. Napoleon sketched and the deduction drawn from it is perhaps one of the most curious and interesting passages that ever emanated from the imperial press. From what we have just read says the author "results I think very evidently this tranquillizing truth that the barriers of the French empire are absolutely inexpugnable by any power or coalition of powers whatever if well defended".-Observations on modern systems of fortification: including that proposed by ...1859, by General Sir Howard Douglas.  And:

This line of defense would be enacted against a siege force against a fortification, meaning that the line of the attacker would be close at  100+yards away (or hundreds of yards away) given the ballet of how these things were supposed to be done in the history of sieges. The"vertical fire" is the fortified force using mortars and etc. launching their shot with lots of powder at an extreme angle  because it seems as though Carnot somehow depended on the velocity of the shot falling from the vertex of the curve to inflict the damage on the soldiers of the opposing side. Terminal velocity being what it is, a major league pitcher could almost pitch a bullet as fast as the falling projectiles. To have a rain of such things--even by the tens of thousands--doesn't seem to be very practicable. I think this just goes to show that in spite of the enormity of Carnot's name and achievements, this part of his engineering career doesn't seem to be very distinguished--unless I'm wrong about this, and if so I hope someone will point that out to me and explain how the rain of fire made sense. 

Notes:

The Quarterly Journal of Science, Literature, and the Arts, volume VIII, London, John Murray, 1820. iii,iii, 412pp, with five engravings, three folding.  Nicely bound in calf backed marbled boards, with calf tips, with gilt-stamped paneled spine. There is a gilt-stamp on the spine reading "Ex lib Soc Reg Sco". Also included in this volume: "On the Mammoth, or Fossil Elephant, found in the Ice, at the Mouth of the River Lena, in Siberia. From the Fifth Volume of the Memoirs of the Imperial Academy of Sciences of St. Petersburg", pp 95-107; [Laplace] "On the Figure of the Earth", pp 108-114 (from the Annales de Chimie, volume XI); William Philip, "Some Observations relating to the Agency of Galvanism in the Animal Economy...", pp 72-83; "Description of Messrs. Taylors and Martineau's Patent Apparatus for the Production of Gas from Oil...", pp 120-124 (that would be John Martineau and John Taylor, who joined in a company to produce machines and fuel flourishing in the 1815-1830 period, though for most of that time Taylor would not be a part of it), among others.