412 



NATURE 



[August 28, 1890 



Niven's D into circular measure, or natural tangents, and 

 called it I ; and has added another useful function, A, 

 the altitude function. The use of these functions is indis- 

 pensable in modern ballistics ; but Mr. Bashforth does 

 not mention them, as the chief purport of his book seems 

 to be to put on record his own share of the work ; 

 and certainly, once the experimental part is done, it is 

 a very easy matter to sit quietly indoors and theorize 

 upon it. 



A very searching test of Mr. Bashforth's tables was 

 proposed in 1887, when it was decided to fire the 

 " Jubilee rounds " from the 9*2 inch at elevations of 40°- 

 45°, to see what is the extreme range attainable with 

 modern artillery ; and calculations were invited, to be 

 sent in before the gun was fired. Mr. Bashforth prints 

 the result of his calculations, which assigned a range of 

 19,426 yards with an elevation of 40° and an initial 

 velocity of 2360 f.s. The range attained one day when 

 the gun was fired was over 21,000 yards, and on another 

 day was over 20,000, the difference being attributable to 

 wind ; so that, with no allowance for wind, and the fact 

 that the initial velocity was really about 2375 f.s., we 

 must consider that the calculation was close enough to 

 show the value of Bashforth's coefficients ; other calcu- 

 lators who allowed for the better shape and steadiness of 

 the projectile obtaining even closer agreement. The 

 calculation is interesting as showing the great height to 

 which the projectile rises, and the consequent necessity 

 for a frequent change in the coefficient of resistance due 

 to the tenuity of the atmosphere. 



Prop. VII., Robins's " New Principles of Gunnery," 

 asserts : — " Bullets in their flight are not only depressed 

 beneath their original direction by the action of gravity, 

 but are also frequently driven to the right or left of that 

 direction by the action of some other force." 



This well-known effect in golf is still more marked in 

 rifled artillery, especially with high-angle fire ; and now 

 in modern ballistic tables we have columns added for M 

 and B, two functions calculated theoretically by General 

 Mayevski, for assigning the value of this lateral devia- 

 tion or drift. 



Mr. Bashforth devotes chapter vi, to a popular ex- 

 position of this phenomenon, which is still somewhat 

 wrapped in obscurity, in spite of all that has been written 

 about it ; a list of which writings is given by Captain 

 Ingalls in his " Hand-book of Problems in Exterior 

 Ballistics." 



The stability of the axis of the projectile imparted by 

 the rotation has the effect of making the head of the shot 

 point slightly to the right of the vertical plane of fire with 

 right-handed rotation, thus causing drift, and also of 

 keeping the head a little above the tangent of the tra- 

 jectory, so that in its descent the shot experiences a so- 

 called kite-like action, tending to increase the range. It 

 is well, however, for theorists to be on their guard in 

 offering an explanation, as observers are not always 

 agreed as to what really takes place. 



Mr. Bashforth expresses a fear that, after all his labours, 

 he will have produced very little effect ; but we hasten to 

 reassure him that his work is held in the highest estima- 

 tion by those who have means of making a practical 

 judgment. 



A. G. Greenhill. 

 NO. 1087, VOL. 42] 



BRITISH FOSSILS. 

 British Fossils, and where to seek them; an Introduction 

 to the Study of Past Life. By J. W. Williams. Pp. 96, 

 Illustrations. (London : Swan Sonnenschein and Co.^ 

 1890.) 



A T the close of the introduction to this little volume, 

 -^ the author informs us that his object has been to 

 convey to the young collector of British fossils the ex- 

 perience and knowledge acquired by others, whereby his 

 own toil and labour may be lightened. The purport of 

 this is admirable, but unfortunately the author has not 

 succeeded in carrying out his good intentions. The 

 volume is small, and merely a compilation ; so there is 

 no excuse for the number of errors and misprints by 

 which its pages are disfigured. 



The plan of the book seems to be to give a brief notice 

 of each main geological horizon, with a list of some of the 

 characteristic fossils, but we very much doubt whether 

 long strings of generic names, like those given on p. 28, 

 for example, are calculated to afford much assistance to 

 the young collector, as there is practically no information 

 as to what such terms really represent. None of the 

 illustrations are original, the frontispiece being taken from 

 Louis Figuier's " World before the Deluge," and most of 

 the other figures from a well-known German work. And 

 while on the subject of illustrations we should be glad to 

 be informed why amphibians and reptiles like Archego- 

 saurus, Capitosaurus, and Placodus, should have their 

 skulls figured (as on pp. 45, 46) in a work on British 

 fossils, when these genera are totally unknown from 

 British strata. Such figures, as well as those on pp. 56, 

 57, may lead the inexperienced " young collector," for 

 whom the book is avowedly written, to the conclusion that 

 he may expect to meet with entire skulls and skeletons 

 of fossil reptiles in his geological excursions. The proper 

 course in these cases is, it need hardly be said, to give 

 figures of teeth and some of the bones of such creatures,^ 

 with which the tyro may be expected to meet, and to 

 show how their generic affinities can be determined. 

 Then, again, in reproducing the old figures of the Devonian 

 fishes given on p. 33 the author might surely have alluded 

 to the work of Dr. Traquair and other authorities show- 

 ing how very far these figures are from being a truthful 

 representation of these ancient creatures. 



Leaving the illustrations, we may turn to the text. In 

 glancing over the pages we were greatly puzzled to 

 know what might be the meaning of the term dennoid iyp&s 

 mentioned on p. 20, the repetition of the word indicating 

 that it can scarcely be a misprint. Omitting mention of 

 numerous misprints, obvious enough to the specialist, but 

 terribly misleading to the beginner, we notice on p. 29 that 

 Tentaculites is given as an Annelid, although its Pteropod 

 affinities have long been known. Much discussion has 

 taken place as to the affinities of the Palaeozoic plant 

 known as Sphenophyllum, but when on p. 43 the author 

 calmly tells us that it is probably founded on the leaves 

 of Calamites, he gives us a piece of information as new 

 as it is erroneous. It is somewhat amusing to find 

 the student referred, on p. 44, to the author's book on 

 " Land and Fresh-water Shells," as if it were the only 

 extant treatise on the subject ; but when on p. 45 we are 

 informed that Labyrinthodonts are characterized as a 



