6o6 



NA TURE 



{April 29, 1886 



W 6 

 1093 

 1080 

 1063 

 105 '6 

 105-9 

 io5'o 

 104-4 

 103-2 

 101-2 

 99-1 

 980 

 947 

 93 "o 

 927 

 91-9 

 90-4 

 89-2 

 87-9 

 86-7 



i^ o 



g 1 2 



42'I 



42-6 



42-4 



43 '6 

 46-1 



47 'o 

 48-2 

 486 

 47-8 

 467 

 47 'o 

 43 '9 

 43 '2 

 44-6 

 45 '2 

 44-6 



43 '6 

 42-4 



41 "3 

 37-9 

 38-9 

 40-4 

 41-8 

 43 'o 

 43'3 

 437 

 45-0 

 42-4 

 41 o 

 39 '4 

 37 'o 

 37-8 

 42-5 

 41-9 

 41-8 

 41-8 

 35-2 

 36-3 

 367 

 37-4 

 38-2 

 38-6 

 35-2 

 37-8 

 40-8 

 35'9 

 36-8 

 34-2 

 34-1 

 33-9 

 35-3 

 36-4 

 36-3 

 35-4 

 357 

 36-6 



37-3 

 38-2 

 38-4 

 397 

 402 



39'5 

 40-3 

 41 4 

 42-5 

 42-6 

 43'i 

 Mean value of /■ = 14 



82-8 

 Srs 

 80-1 

 78-3 

 78-3 

 80-5 



797 

 79-2 

 78-8 

 74-7 

 74 '9 

 747 

 747 

 747 

 74-5 

 72-3 

 73-3 

 74-5 

 71-5 

 71-6 

 69-9 



69-5 

 69-0 

 69-4 

 69-6 

 69-2 



68-3 

 68-3 

 68-4 

 68-2 

 68-5 

 68-4 

 67-7 

 67-8 



67-9 

 67-8 



+ 0-5 

 + II 



+ 0-9 



+ 2'I 

 + 4-6 

 + 5-5 

 + 6-7 

 + 71 



+ 6-3 

 + 5-2 

 + 5-5 

 + 2-4 



+ 17 



+ 3'i 

 + 37 

 + 3-1 



+ 2-1 



+ 09 

 -02 



-3-6 



- 2-6 



- I I 

 + 0-3 



+ 1-5 



+ 1-8 



+ 2-2 



+ 3-5 

 + 0-9 



67-6 

 67-8 

 67-5 

 67-5 

 67-1 

 67-0 

 67-0 

 67-0 

 66-9 

 66-9 

 66-9 

 66-9 

 66-9 

 66-8 

 66-8 

 66-8 

 677 

 66-9 

 66-9 

 67-0 

 66-1 

 64-4 

 64-6 

 64-6 

 2360 64-6 

 2370 63-8 

 2380 63-7 

 2390 61 -o 



2120 

 2130 

 2140 

 2150 

 2160 

 2170 

 2180 

 2igo 

 2200 

 2210 

 2220 

 2230 

 2240 

 2250 

 2260 

 2270 

 2280 

 2290 

 2300 

 2310 

 2320 

 2330 

 2340 

 2350 



43 '3 



44 '4 

 44'5 

 45 •■ 

 44 '9 

 45 '4 

 46-1 

 46-7 

 47-2 

 47-8 

 48-5 

 49-2 

 49 '9 

 50-3 

 51 o 

 51-6 

 54'4 

 53-2 

 53'9 

 54'8 

 53'4 

 50-1 

 51-2 

 51-8 

 52-5 



51-2 



5--6 

 45-8 

 43-5 

 427 

 38-2 

 38-8 

 33 'o 

 29-4 

 28-4 

 289 

 297 

 30-2 

 30-8 

 31-5 

 320 

 32-8 



ly^ 



34'i 

 34 '9 

 35-4 

 37-8 

 38-6 

 39 4 

 39 9 

 40-7 



41-5 



39 '4 

 39 '9 

 40-1 

 40-6 

 41-2 

 41-7 

 42-2 

 42-7 

 43 '2 

 45 '4 

 46-0 



+ i-S 



+ 2-9 



+ 3-0 



+ 3-6 



-t- 3'4 



+ 3-9 



+ 4-6 



+ 5-2 



+ 57 



+ 6-3 



+ 7-0 



+ 77 



+ 8-4 



+ 8-8 



+ 9-5 



+ IO-I 



+ 12-9 

 + 11-7 

 + 12-4 

 + i3'3 

 + 11-9 

 + 8-6 

 + 9-7 

 + 10-3 

 + 110 

 + 9-7 

 -I 101 



+ 4-3 

 + 2-0 



+ 1-2 



~ 3'3 



- 2-7 



- 8-5 

 -12-5 



- 13 I 

 -12-6 

 -II -8 



- 1 13 



- 10-7 



- 100 



- 9-5 



- 8-7 



- 7-9 



- 7-4 



- 6-6 



- 6-1 



- 37 



- 2-9 



- 2-1 



- 1-6 



- 0-8 

 00 



- 5-5 



- 3'4 



- 3"2 



- 2-7 



_ 2 I 



- 1-6 



- 1-4 

 _ 09 



- °'3 



+ 0'2 



+ 0-7 



+ 3'9 

 + 4-5 



to 2780 feet per 



I have recently calculated some ranges of elongated 

 shot for low elevations, starting with a ni.v. of 1900 f.s , 

 allowing 6' for "jump." The following are the results 

 obtained : — 



Experimental range. 

 Calculated range 



Difference . 



10S6 

 1049 



181 1 2400 2917 yards 

 1814 2392 2896 „ 



-37 +3 -S 



In the Final Report (pp. 43-45) will be found calculated 

 ranges for comparison with range tables, both English 

 and German, for upwards of 1 20 ranges fired with muzzle 

 velocities below 800 f.s. Taking the best of the English 

 comparisons where the m.v. was 751 f.s. ; — 



Exp. range. 

 Cafe. ,, . 



978 

 973 



1788 

 1780 



2467 

 2462 



3000 

 3027 



3467 3813 4000 yds. 

 3473 3804 4013 .. 



•5 +27 +6 



The worst was for a m.v. of 628 f.s. 



Elevation 



Exp. range. 

 Calc. ,, . 



1236 

 1290 



1767 

 1805 



2231 



2242 



2683 

 2593 



3017 3194 yds. 

 2S58 3037 ., 



Difference ... +7 +54 +38 +11 -90 -159 - IS7 ,, 

 The best German comparison was with a m.v. of 705-4 



Exp. range. 

 Calc. ,, ., 



Difference 



875 

 807 



159S 

 1591 



2221 2729 3139 3452 yds. 

 2214 2730 3143 3449 „ 



The worst was for a m.v. of 774-3 f.s. 



Exp. 

 Calc. 



Difference 



1020 

 1028 



1900 

 187S 



2659 

 2590 



3274 

 31S1 



3745 4130 yds. 

 3641 3987 „ 



-69 



■93 



104 -143 



The calculations were all made for the English pro- 

 jectiles where (/^-=- 7f' = -5616, while for the German pro- 

 jectiles ^--H Tt' = -5785. If the latter value could have 

 been conveniently used for the German ranges, &c., the 

 calculated ranges would have been slightly reduced, 

 which would generally have given a still better agree- 

 ment between experiment and calculation. 



Since the publication of my Final Report (1B80) several 

 pamphlets treating of the resistance of the air have been 

 issued from the private printing press of M. Krupp. The 

 main object seems to have been to persuade the world that 

 the Krupp system entails a lower resistance to the shot than 

 that encountered by the English system. The difference, 

 if any, appears due to the more pointed form of the Essen 

 projectile, and to the lower density of the air adopted. 

 In general no sufficient explanation is given of the parti- 

 culars of the experiments made. But in the paper (xxx.) 

 some details have been furnished of experiments under- 

 taken at IS^eppen (1S81) to try whether the resistance of 

 the air varied as the square of the velocity for velocities 

 above 400 m.s. Supposing this to be the case, an expres- 

 sion was found for X tlie coefficient of resistance in terms 

 of the velocities of the shot at two points in its course, the 

 distance between them, &c. 



.SY.r chronoscopes were distributed in pairs — one pair 

 being placed at A, 30 metres from the gun ; another pair 

 at B, 130 metres from the gun ; and the reinaining 

 pair at C, 500, 1000, &c., metres from the gun. The 

 experiments were arranged in groups. We will examine 

 group 3, formed of rounds 7, 8, 9, and 10. The mean 

 velocity at A was stated to be 900-1 m.s. ; at B, 

 853-2 m.s. ; and at C, 438-1 m.s. Taking the range A C, 

 the value of Xio'^ was found 3-585 ; and the range B C 

 gave 3-700 ; so that the mean of the two was 3-64. The 



