SHOUT NOTES OH UUOEESSIONAL SUBJECTS. 
13 
consider the case of projectiles fired east or west, it is so easy in the case of those 
fired north or south, that a few minutes explanation will convince any intelligent 
person of its reality (see “Proceedings,” Yol. IV. p. 45 5). No experiments were made, 
but Lord Palmerston’s letter may be added to the literature of the subject, as not 
the least curious illustration of the interest guns and gunnery possess for the active 
minds of our day. L. 
December 20, 1857. 
“My beau Panmure, 
“ There is an investigation which it would be important and at the same time 
easy to make, and that is whether the rotation of the earth on its axis has any 
effect on the curve of a cannon-ball in its flight, one should suppose that it has, 
and that while the cannon-ball is flying in the air impelled by the gunpowder, in a 
straight line from the cannon’s mouth the ball would not follow the rotation of the 
earth in the same manner which it would do so if lying at rest on the earth’s 
surface. 
“If this be so a ball fired in the meridional direction, that is to say, due north or 
due south ought to deviate to the west of the object at which it was aimed, because 
during the time of flight, that object will have gone to the east somewhat faster 
than the cannon-ball will have done. 
“ In like manner a ball fired due east ought to fly less far upon the earth’s 
surface than a ball fired due west, the charges being equal, the elevation the same, 
and the atmosphere perfectly still. It must be remembered however that the ball 
even after it has left the cannon’s mouth will retain the motion from west to east 
which it had before received by the rotation of the earth on whose surface it was, 
and it is possible therefore that except at very long ranges the deviations above 
mentioned may in practice turn out to be Very small, and not deserving the attention 
of an artillery-man. 
" The trial might easily be made in any place in which a free circle of a mile or 
more radius could be obtained, and a cannon placed in the centre of that circle, and 
fired alternately north, south, east, and west, with equal charges, would afford the 
means of ascertaining whether each shot flew the same distance or not. 
“ Yours sincerely, 
“PALMEKSTON. 
ic It has been ascertained that the rotation of the eafth produces a sensible effect 
on the oscillating pendulum.” 
19 Photo-Lithography as practiced in the Eoyal Carnage Department, 
Woolwich.^ The process is the same in principle as that of photo-zincography, 
invented by Colonel Sir H. James, E.E., but is specially worked out in its details 
to suit the particular subjects upon which it is employed in the above department. 
Such subjects being chiefly line drawings of artillery material; the lines being very 
fine, and the details s'o small and intricate, that unless very sharply rendered in the 
reduced photo-lithographic copy they would be unintelligible. 
As in the photo-zincographic process, a mixture of gelatine and bichromate of 
potash on sheets of paper is used as a medium for receiving and transferring to stone 
^ By Mr H. Butter* chief draughtsman, Eoyal Carriage Department; 
