446 



NA TURE 



[September 5, 1901 



that the projectile would be deflected upwards by the resistance 

 of the air, so as to increase the elevation for which the gun was 

 laid. This was named "kite-like action" in England, and 

 Didion remarked that there would be a considerable deviation 

 of the projectile " tant dans le plan verlical, que dans le plan 

 horizontal" {Traiti'. xiii. i860). Suppose now that the range >■ 

 and the time of flight /, for an elevation a, have been carefully 

 calculated. Then from the range table of the same gun, 

 corresponding to same range r, find /' the time of flight, and a 

 the elevation. Then if / = /' the coefficients of resistance giving 

 the required time and range, are correct, and a - o' is due to kite- 

 like action. Thus, using the range table of the 4-inch B.L. gun : 

 r'=i90of.s. ; ■w = 2^ lbs. ; a=i2°; and k = 0'97. 



Here for a range of over three miles, the calculated and ob- 

 served times of flight, from point to point, differ by only o"'044. 

 a negligible quantity. The resistance of the air must therefore 

 have increased the elevation, for which the gun was laid, by 

 a - o' = 34', due 10 jump and kite-like action, for an elevation of 

 the gun of 11° 26'. The whole range table of the 4-inch B.L. 

 gun was thus treated in 1892 (Nature, No. 1190), These 

 calculations have recently been repeated for elevations 7° to 20°, 

 and published in my Second Supplement, where all the leading 

 steps in the calculation of the ranges, &c., have been given. It 

 was then found that when an elevation of 7° is given to the gun, 

 21' is added to the elevation by kite-like action, so that 7° 4- 21' 

 must be used for the elevation when it is required to calculate 

 the range and time of flight for an elevation 7° of the gun. The 

 elevation of the gun is given in degrees below, and the addition 

 thereto m.ade by kite-like action and jump is given in minutes, 

 7'-t-2i', 8°-f 23', 9° -I- 26', 10° -I- 29', ii°4-33', i2°-f 38', 13°-!- 45', 

 i4° + 53'. '5° + 63', i6°-F74', i7°-h86', 18° -1-98'. 



From the results of calculations of range and time above re- 

 ferred to, I have deduced the following table : — 



showing clearly that both range and time of flight — given by 

 experiment and calculation — agree, when a proper allowance is 

 made for jump and kite-like action. 



From the fair application of all these tests, it appears that 

 calculated and experimental ranges and times of flight agree 

 perfectly well for all practical purposes. Hence the laws of 

 resistance determined by me— the general tables published by 

 me — and the adaptation by me of J. Bernoulli-s method of 

 calculating trajectories are all quite satisfactory. But care will 

 be required not to make my methods responsible, in any way, 

 for the disturbing efl'ects of jump or of kite-like action. Con- 

 sequently range tables cannot at present be prepared by calcula- 

 tion alone, but when obtained by experiment, they may be 

 tested at any point by the method {7) already explained. 



This chronograph might be used with great advantage to test 

 the shooting qualities of all big guns. For this purpose the 

 elongated projectiles should be provided with heads of similar 

 forms. The charges used should be such as would give the 

 velocity v, for which the gun is to be tested, near the middle 

 screen. Fire each projectile through the equidistant screens 

 till « satisfactory rounds have been obtained. Calculate K,,', 

 K„", &c., for each of these rounds. Then the approximate 



NO. 1662, VOL. 64] 



value of K„= -(K„'-f K„"-H&c.), and the mean error will be an 



indication of the steadiness imparted by the gun to its projectile, 

 and so on for any number of guns. The shooting qualities of 

 any guns could be compared for the velocity v, by simply com- 

 paring the numerical values of K^ given by each gun — the lower 

 the numerical value of K„ the better the shooting. Target 

 practice might be carried on simultaneously with these screen 

 experiments. The best of the guns taken in South Africa should 

 be brought home and tested in the manner above recommended. 

 August 1901. F. Bashkorth. 



Horn-feeding Larvee. 



So far back as June, 189S, you published in Nature 

 a short article from my pen dealing with " Horn-feeding 

 LarviE " ; it opened up the question as to whether the larvee of 

 the insect Tinea vastella, Zell. = giganlclla, Stn. = Incidella, 

 WKr. , fed on the horns of living animals. I mentioned at the 

 time that Dr. Fitzgilibon, in 1856, brought home from the 

 Gambia two pairs of horns, one belonging to Koltis ellipsi- 

 prymnns and the other to Oreas canna, which he had purchased 

 from the natives ; the horns were perforated by grulis enclosed 

 in cases which projected abundantly from the surface of the 

 horns, the blood at the base of the horns not having thoroughly 

 dried up on them when brought to market. 



Dr. Henry Strachan, of Lagos, wrote a letter, dated July 22, 

 1898, which appeared in Nature, and in that letter he stated 

 that the living horns were attacked and infested with the larv^, as 

 cocoons and pupce had been extracted from such horns within an 

 hour of the killing of the animals owning them. This he states 

 on the unimpeachable authority of an officer who made the 

 obser%-ation. 



During 1899, 1900, and until July of this year, I have 

 travelled very considerably in West Africa, having spent these 

 years in Northern and Southern Nigeria, as well as Ashanti and 

 the hinterland of the Gold Coast ; I have made close observation 

 of many species of horned animals, and have spent many days 

 with native big game hunters. I have seen many cases in which 

 the horns of dead animals have been infested with the larvje of 

 the Tineidae, but have never met with it in those of living 

 animals. The natives with whom I have been associated, who 

 are keen hunters and extremely keen observers, assure me they 

 have never seen any protuberances containing grubs on the 

 horns of living animals. During our campaign in Ashanti, I 

 ()uestioned officers who came with troops from all parts of the 

 West Coast as well as the East Coast of Africa ; also soine from 

 Uganda and the Lakes : they all unhesitatingly say that they 

 have never seen cocoons on living animals, although well 

 acquainted with them on the horns of dead animals. Dr. 

 Fitzgibbon's statement stood alone until Dr. Strachan's letter 

 appeared. I venture to suggest that the point still remains 

 Slid jtidice. W. J. HUME McCoRQUODALE. 



August 30. 



NEW GARDEN PLANTS: A STUDY IN 

 EVOLUTION. 



THE appellation "new garden-plants" is rather 

 puzzling to those who are neither botanists nor 

 gardeners, and, indeed, it is used with somewhat dififerent 

 significations by both these classes of experts. Con- 

 sidering that not the least of the many services rendered 

 by the Royai Gardens, Kew, is the annual publication, 

 as an appendix to the Ki"-u< Bulletin, of a list of " new 

 garden plants," some explanation of what is meant by this 

 designation may not be without interest. Let us take an 

 illustration. The maidenhair tree, Ginkfi;o tn'loba, was 

 in reality introduced into our gardens in 1750 or there- 

 abouts. But let us suppose for our present purpose that 

 it was introduced only in this year of grace 1901. Would 

 it in that case have any right to be considered a " new 

 plant"? If we look on it as the direct lineal descendant 

 of a tree that grew in (.Greenland in Miocene times and 

 had its ancestry still further back in the Oolitic period, we 

 could hardly consider it as "new." The only novelty 

 about it would be its introduction into gardens. Similarly, 



