CAUSES OF DRIFT. 233 
experiment, which was made after I had remonstrated on the inconclu- 
sive character of that with the three incorrectly termed flat-headed shot, 
the detailed results of which were not published. 
The following are the particulars of the experiment made on Ist 
August, 1873, at Shoeburyness, and this time, having notice, I attended. 
An Ll-inch M.L.R. gun of 24-tons, 19-cwt., 2-qrs. was used. The pro- 
jectiles called service were strengtened common shell, weighted with 
lead up to 935-lbs.; those termed flat-headed were proof shot of the 
same weight. The charge was 85-lbs. of pebble powder. 
The rounds were fired in three series of six each; three of these six 
being service, and three flat-headed, fired alternately. 
FIRST SERIES. 
: Nature of ‘ 
Round. Elevation. Projectile. anes: eee 
lp 6° by boo NEL. coo CODE 36 Right. 
2 ...f Quadrant ... Service ... 3192 ... 6:0 rs 
3 ta Py EH we 3025... 50 
4 Brad RY aie (Service eamSotO Me e.08, 8! 
s angent : : 
5 aaa JIL Sehos SURO! eS EO 
6 : Service ... 3223 64 _ 
SECOND SERIES. 
7 .. FH. 20S 90 Right. 
8 oye cco STAKE —c00 PS con OD) 
9 Tie at, § Wes IR ek Oo 
lamer Soule Service ... 2260 .. 80 ,, 
Eee a1 )de. SHH? .. 2200 6:0 ee 
LQ wees NS CLV COMES MELO. 6°4 mM 
THIRD SERIES. 
Teach 20 . EH. .. 1310 30 Right, 
14 we =e SeCEVICE ee 322) ewe 3:6 A 
15 ...{ 2022/by ... FH. .tHL360p Merss-oem We 
1G 5 Tangent ... Service ... 1358 1:0 “a 
17 =| Scale. ... FH... 1326 Sciam 
1G coc wee etvice s.. alt 16 " 
In looking at these results it is apparent that the deflections of both 
kinds of projectiles were to the right ; but on examining the proof shot 
I found that they were after all not cylindrical, the point only being 
flattened, while the shoulders were rounded off, and the results being 
therefore of no value. This I pointed out in a letter to the Secretary 
of the Department of the Director of Artillery in the following 
words :—“ The results of the practice with 11-inch proof cylinders and 
shell on the Ist August, 1873, at Shoeburyness, are in my opinion of no 
value whatever from the fact of the so called flat-headed cylinders 
being considerably rounded off in front (radius 1-45), I pointed this 
out to Colonel Fisher and Captain Jones, who said he attended for 
Major Maitland.” 
“The projectiles used in former experiments to test deflection were 
true cylinders, and I have always been careful to say jlat-headed or 
cylindrical, and to give diagrams with such form (see ‘Modern 
Artillery.) ‘This rounding off which might at first sight appear unim- 
portant is a vital point. By calculation, it may be found that by thus 
rounding off the ll-inch cylinder (reducing the diameter of the 
31 
