12 
SHORT NOTES ON PROFESSIONAL SUBJECTS, 
The mean height of the barometer was 30 inches, and the mean temperature 
60’5° E. As the solid and hollow ogival shot (1 diameter) had the same external 
form, the pressure of the air resisting the motion of each at a velocity of 1250 ft. 
ought to be the same. 
lbs. 
The mean of ten rounds of hollow shot (ogival, 1 diameter), gives 146-2 
The mean of two rounds of solid shot « „ 147’9 
The solid and hollow ogival shot (2 diameters), had the same external forms. 
The mean of eight rounds of hollow shot, ogival (2 diameters), gives 139-9 
The mean of Uoo rounds of solid shot « „ 146*8 
From the small differences in the amounts of the resistance of the air offered to 
ogival headed and spheroidal headed shot, it is manifest that, for practical purposes, 
it is not necessary to make any further experiments with the 40-pr. gun, except 
perhaps the remaining rounds might be fired when opportunity offered. It is 
probable also that the resistance of the air to any useful forms of heads for any 
other bore would not differ much among themselves. 
The reason why the resistance of the air varies according to a higher power 
of the velocity than the second power may probably be found in increased 
volume of air disturbed by the increased velocity of the shot. 
18. Lord Palmerston on the effect of the earth’s rotation on 
projectiles. The following very curious letter was written by Lord Palmerston 
to the Earl of Dalhousie in December 1857, and by the latter referred to the officer 
whom he usually consulted at that period on subjects of gunnery, with the short and 
characteristic note, 
<f My dear —-—- 
“ Bead and inform me on the abstruse philosophy of our Prime Minister, I 
wonder where we are to find a circular range of a mile radius. 
** Ever yours, 
" PANMUBE.” 
It is now printed with Lord Dalhousie’s kind permission, as a document pre¬ 
eminently interesting to artillerymen, and a more remarkable proof perhaps than 
many weighty state papers would afford, of the clear head of the great statesman. 
The subject must have been wholly new to Lord Palmerston. The letter suggests 
to us that somewhere in London society, he fell in with a person conversant with 
it, gave him his full attention, took a vigorous grasp of the question, revolved it 
in his own mind, and next day sat down in the midst of all his other avocations to 
suggest to his War Minister that experiment was required to determine the real 
amount of this new influence on projectiles. It was of course easy to satisfy Lord 
Panmure that the problem is one which does not require appeal to experiment at 
all. The effect is a necessary consequence of mechanical laws long since ac¬ 
knowledged as beyond dispute, and although it presents some difficulties when we 
