April 22, 1909J 



NA TURE 



237 



denser arrangement of Dr. Fleming was replaced by a 

 single condenser, the arrangement being similar to that 

 shown in Fig. 3. 



During the time that constructional work was in progress 

 at Glace Bay, I carried out some tests with Poldhu over 

 considerable distances, and these tests were greatly facili- 

 tated by the interest taken in them by the Italian Govern- 

 ment, which placed the cruiser Carlo Alberto at my dis- 

 posal. 



During these experiments the interesting fact was 

 observed that, when using waves of more than 1000 metres 

 in length, intervening land or mountains do not bring about 

 any considerable reduction in the distance over which it is 

 possible to communicate. Thus messages and Press des- 

 patches were received from Poldhu at the positions marked 

 on the map (Fig. q), which map is a copy of the one 

 accompanying the official report of the experiments (Revista 

 Marittiitia, Rome, October, 1902). 



In December, 1902, messages were for the first time 

 exchanged at night between the stations at Poldhu and 

 Glace Bay, but it was found that communication was ex- 

 ceedingly difficult and untrustworthy from England to 

 Canada, whilst it was good in the opposite direction. The 

 reason for this is that the Glace Bay station was equipped 

 with more powerful and more expensive machinery — a con- 

 dition rendered possible by the subsidy granted by the 

 Canadian Government ; whilst as regards Poldhu, owing to 



"^ FIC. 9 



TR«Ce or CHCARLO-kLBEriiTi; 



" "Tab™ 



the uncertainty of what might or might not be the attitude 

 of the British Government at that time towards the work- 

 ing of the station, my company was unwilling to expend 

 large sums of money for the purpose of increasing its range 

 of transmission. 



As, however, messages could be sent then for the first 

 time by wireless telegraphy from Canada to England, 

 inaugural messages were dispatched to the Sovereigns of 

 England and Italy, both of whom had previously given me 

 much assistance and encouragement in my work, and who, 

 by their gracious replies, attested their appreciation of the 

 results which had been achieved. Other messages were 

 also sent to England by the Government of Canada. 



Further tests were shortly afterwards carried out with 

 the long-distance station at Cape Cod, in the United States 

 of .America, and a message from President Roosevelt was 

 transmitted from that statio'n to His Majesty the King in 

 London. 



It is curious to note, in regard to the transmission of 

 this message, that the energy employed at Cape Cod was 

 barely 10 kilowatts, and it was not anticipated that this 

 amount of energy would bo sufficient to carry direct to 

 Poldhu. The message was therefore transmitted from Cape 

 Cod, instructions having been given to the operators at 

 Glace Bay to be on the look-out, and to repeat wirelessly 

 on to Poldhu any message received from Cape Cod, and 

 my assistant, Mr. P. J. Woodward, at Poldhu, took in the 

 message on one of mv magnetic detectors.* The electro- 

 magnetic waves conveying this message travelled, therefore, 

 3000 miles through space over the .Atlantic, which distance 

 included about 500 miles of land, following an arc of 

 45 degrees on a great circle. 



(To be continued.) 



' Proc. Roy. Soc, lxx.,p. 341, " Note on a Magnetic Detector of Electric 

 Waves which can be employed as a Receiver for Space Telegraphy." 



NO. 2060, A'OL. 80] 



THE PHYSICS OF GOLF.. 

 [ N two articles recently published in the Times (March 

 ■'■ !b and 23) Sir Ralph Payne-Gallwey has e.xtended in an 

 interesting way the earlier results in the physics of golf 

 which the late Prof. Tait communicated to N.\ture between 

 the years 1887 and 1894. In Sir Ralph's experiments the 

 golf balls were projected mechanically by means of a 

 catapult, the ball being either thrown from a cup at the 

 end of the rotating arm or hit off as it hung at the end 

 of a gossamer thread by a blow from the arm. In either 

 case the initial conditions of projection must differ from 

 those which exist in the ordinary mode of propulsion, and 

 it would have been interesting to have had some com- 

 parisons. As Tait conclusively showed, the great factor 

 in long driving was the underspin communicated to the 

 ball by the impact of the club in a line below the centre 

 of gravity. Hence the value of the roughened ball, causing 

 not only a better grip between the ball and the club, but 

 also making more efficient the effect of the resistance of 

 the air in producing the uplifting force. Sir Ralph Payne- 

 Gallwey shows experimentally that the ball must not be 

 too much roughened, and that, indeed, a distinctly less 

 roughening than is usual is sufficient to ensure the maxi- 

 mum carry. It is obvious that with a very rough surface 

 the resistance of the air will rapidly cut down the rotation, 

 and thereby diminish the transverse force which lifts the 

 ball against gravity. 



Sir Ralph does well in directing attention to the 

 necessity of a truly centred ball. The golfer can readily 

 test the' ball in this respect by floating it in water (Tait 

 used to use mercury) and noting whether or not it 

 comes quickly to the same position. If it comes 

 quicklv always to the same position it is badly centred, 

 and niust be rejected. As all bowlers know, the lack of 

 true centring will give a bias which cannot but produce 

 inaccurate putting. In the flight through the air the b.ad 

 effects due to the centre of gravity being non-coincident 

 with the centre of figure will probably come into evidence 

 because of the shifting of the axis of rotation. Such a 

 badlv centred ball, when projected from the tee, will in 

 general be sent off rotating about an axis which, though 

 initially horizontal, is not a principal axis of inertia. Of 

 necessity precessional motion will result, and the axis of 

 spin win move awav from its horizontal position. The 

 phenomena which lead to the evils of slicing and pulling 

 will at once declare themselves. Moreover, if the pre- 

 cessional motion be rapid enough, it is conceivable that 

 the ball might swerve in one direction during one part 

 of its course, but in the other direction during another 

 part of the same trajectory. A sinuous flight is. indeed, 

 occasionally observed, but 'is generally attributed to the 

 direct action of the wind. Sir Ralph Pavne-Gallwey does 

 not himself touch upon the ultimate dynamics of the 

 oroblem, but confines himself entirely to the direct teach- 

 ing of experiment. His conclusions are of great practical 

 value to all devotees of the game, and it would be well 

 if the manufacturers of golf-balls would test every ball 

 thev put on the market by the simple methods described 

 bv him. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



TiiK Bristol Town Council has decided to contribute in 

 the proportion of one penny in the pound on the rate, or 

 about yoooZ. per annum, towards the support of the pro- 

 posed university for Bristol and the West of England, 

 for which more' than 200,000/. has been subscribed, mainly 

 bv members of the Wills family. 



The estimate of the amount required in the year end- 

 ing March 31, 1910, for grants in aid of the expenses of 

 certain universities and colleges in Great Britain is 

 ^17400/. The following are the sub-heads under which 

 this vote will be accounted for by the Treasury. Grants 

 in aid, universities and colleges :— (.A) University of 

 London, Sooo!. ; (B) Victoria University of Manchester, 

 >ooo/ ■ (C) University of Birmingham, 2O0O(. ; (D) Uni- 

 versity of Wales, 4oooZ. ; (E) University of Liverpool, 

 'ooo/'- (F) Leeds University. 200o(. : (G) Sheffield Uni- 



