THE EOYAL AllTILLEEY INSTITUTION. 
459 
be a diversity of opinion; but perhaps the majority of officers will agree that 
12 horses, 4 abreast, are the greatest number that can draw together effec¬ 
tively at a walk ; l that 8 horses, 2 abreast, are the greatest number that can 
draw together effectively at a trot ; 2 and that 6 horses, 2 abreast, are the 
greatest number that can draw together effectively at a gallop. 
The third step is to consider, first, what is the maximum load that 
12 horses, 4 abreast, can draw effectively at a walk; secondly, what is the 
maximum load that 8 horses, 2 abreast, can draw effectively at a trot; and 
thirdly, what is the maximum load that 6 horses, 2 abreast, can draw effec¬ 
tively at a gallop. The answer to the first question is, in round numbers, 
80 cwt.; that to the second, 40 cwt.; and that to the third, 30 cwt. 
And here the question abruptly leaves the province of mobility and enters 
that of efficacy of fire, the next consideration being the proper weight of the 
projectile for field artillery that walks, field artillery that trots, and field 
artillery that gallops—or in other words, for heavy, medium, and light field 
artillery. The weight of the projectile being settled in each case, the 
number of rounds that ought to be carried in the gun-limber must be 
determined. This is a difficult question, and on its solution depends the 
weight of the limber, which must be reduced to a minimum. The sum of 
the weights of the ammunition and the limber being subtracted from the 
total weight behind the horses, in each of the three cases, the remainder 
gives the total weight of the gun and carriage. The diameter of the shot, 
and consequently the calibre of the gun, is determined by the equation— 
Power of gun = Jj- 
where w is the weight of the projectile, and cl its diameter. The value of the 
equation must be made, within certain limits, a maximum. The calibre of 
the gun being thus found, and the sum of the weights of the gun and 
carriage, being known, the ratio of the weights of the gun and carriage must 
be calculated, on the principle that the weight of the gun should be maximum, 
and the weight of the carriage minimum. 3 
1 I have seen 24 horses, 2 abreast, employed to drag guns through the deep sand on the hanks 
of the river Chumbul, in Central India, but I believe 12 horses, 4 abreast—certainly 16 horses, 
4 abreast—would have done the work more efficiently. In the case I refer to, none of the wheel 
harness gave way, but several traces belonging to the foremost pairs of horses snapped, and one 
of the lead horses burst a blood-vessel in his head. 
2 I am inclined to think the Swedish mode of draught with 8 horses the best— i.e., 3 horses in 
the lead, 3 in the centre, and 2 in the wheel. See Jacobi’s “Etat actuel de l’Artillerie de campagne 
Suedoise; traduit de l’Allemand par Lenglier.” Paris, 1849, p. 88. By shifting the shafts from 
double to single draught, and hooking swingle-trees to the outside trace-hook-eyes, we can work 
three horses abreast in the English field artillery—the lead driver riding the centre leader, and the 
wheel driver the near wheeler. The leading rein of the off wheeler can be lengthened by the 
swingle-tree strap. 
3 I do not venture even to suggest a solution to these problems, because they lie beyond the 
bounds of the subject I am writing on—the Mobility of Field Artillery. Let them be solved by those 
who have studied them carefully and understand them better than I do. See Col. H. H. Maxwell, 
on “The Field Gun for India,” in the “Proceedings, E.A. Institution,” Yol. VI. p. 479; Lieut. 
C. Jones, E.A., on “The Future Armament of our Field Artillery,” Ibid. Yol. VII. p. 252; and 
Lieut. J. Sladen, on “ The merits of a Large Bore and Small Bore contrasted, in reference to 
Bided Artillery,” Ibid. Yol. VII. p. 273, 
