204 



NATURE 



[June 29, 189: 



the well ascertained data 6"5 for the time of flight, and 

 540 feet for the carry, thus obtaining a general expression 

 for V in terms of a. Then, in consequence of the want of 

 accurate data, I chose three values of a, one considerably 

 less than, the second nearly equal to, and the third con- 

 siderably greater than, that which results from Bashforth's 

 experiments with iron spheres. Thus I found the follow- 

 ing values : — 



fault. I regret this for the additional reason that I should 

 have liked to add an illustration of an extremely exagger- 

 ated path in which e is (say) zero, and k unity at the least. 

 Under conditions of this kind there might be kinks in the 

 path ! For a similar reason I cannot attempt to work 

 out the effect of wind with any attempt at precision, at 

 least in the case when the drive is against the wind and 

 the upward concavity of the path becomes in conse- 

 quence much more prominent. It is easy in every case 

 10 form the more exact equations, but the labour of 

 Ireatin.; them even to a rough approximation would be 

 "^onsideriiii'e. 



Next, with each pair of these numbers, and wiih ihe 

 successive values \, ^, and o for e, I found k from the 

 condition that j = o for .r = 540. These values of k 

 are of course greater as e is less, and also as a is less. 

 But all are found to lie between the limits derived, above, 

 from the data for a sliced ball. All the constants 

 being thus found, the curves were easily traced by a few 

 points : — and the position of the maximum ordinate was 

 found as above. For contrast, I have put in (dotted) the 

 paths of drives corresponding in all respects with the 

 others, except the absence of rotation.' Poorly as these 

 show, they are probably unduly favoured at the expense 

 of the others, as I have taken a the same for each 

 of the group ; though it is probably reduced by the 

 spin, so that rotation increases the direct resistance. 

 The comparison of these with those in which rotation has 

 a share shows that, though strength and agility are un- 

 doubtedly of importance in long-driving, even a store of 

 these qualities equalling in amount that of a full-sized 

 tiger is comparatively inefficient as against the skill which 

 imparts a sound undercut. For here, as elsewhere, the 

 race is not to the swift, nor the battle to the strong. 

 Craft beats Kraft all the world over ! La Puissance ! ce 

 n'est pas frapper fort, mais frapper juste ! 



From the very nature of the process I used in 

 approximating, none of these curves can be quite trust- 

 worthy, those giving the greater elevations being most at 



NO. 



1235, VOL. 48] 



I am engaged at present in endeavours to find some- 

 thing like a proper value of a, or of V, above ; so as to 

 have reasonable confidence in my data before I engage 

 in what promises to be a heavy task. Of course, if 1 

 can obtain a satisfactory value of one of them, that 

 of the other would follow. But independent determina- 

 tions of both would enable me to subject the theory to 

 the most complete test imaginable. I am inclined to 

 think that the value of a (280 feet), which I calculated 

 from Bashforth's data, is too large {i.e. it makes the re- 

 sistance too small) for a golf-ball ; — and thus that the 

 true path is intermediate in form between those of the 

 first and of the second series in the cut. For the initial 

 speeds required, even with a = 270, to give a carry of 

 540 feet without spin., are 462 and 653 foot-seconds for 

 slopes of I in 4 and i in 8 respectively : — the corre- 

 sponding times of flight being only 3=^7 and 2^-6. 



P. G. Tait. 



NOTES. 



We are glad to record that the Council of the Imperial 

 University of Kasan has elected Prof. J. J. Sylvester honorary 

 member of the University. 



The Albert Medal of the Society of Arts for the present year 

 has been awarded to Sir John Bennet Lawes and a like medal 



