December 22, 1910] 



NATURE 



251 



monthly temperature for five years (1903-8) varies from 

 968° F. in July to 3254° in January, while the absolute 

 range in the same period was 88°. The temperature 

 variability of the seasons brings out the tendency to a 

 winter continental and a summer oceanic climate. These 

 values are (1904): — spring, 51°; summer, 1-3°; autumn, 

 5-4°; winter, 91°. The year 1904 had a mean annual 

 mperature of 22-4°, which is 096° below the average 

 ; -an of the five years 1903-8. 



The wind directions, which were taken from the move- 



•nts of the lower clouds, since the high land to the 



•St of the observ'atory tended to deflect many winds, show 



prevalence of north-westerly winds. Subsequent years' 



ijservations give west and south-west winds as the most 



frequent, which seems to show that the readings of 1904 



give too high a value to north-west winds. Undoubtedly 



he position of Omond House is such that west and south- 



>t winds would tend to be below what would be re- 



rded in an unexceptional situation. In fact, on further 



nsideration, Mr. Niossman has, we understand, come 



. the conclusion that the wind directions of 1904 are not 



wholly trustworthy. East, and especially north-east, winds 



are conspicuously rare, and the percentage wind frequency 



' >r each season does not materially differ from that of the 



ar. The temperatures associated with these winds are 



great interest, but unfortunately in Mr. Davis's five 



ars' summary no thermal wind-roses are given. Verv 



obably the high temperatures associated with some of 



these apparent westerly winds is partly due to Fohn effects, 



since in May, 1903, that is, in midwinter, an undoubted 



Fohn wind raised the temperature at the site of the 



observatory to 46°, which was only 1° lower than the 



absolute maximum of the year. 



Associated with these prevailing west and south-west 

 inds. which were also experienced by Dr. Xordenskjold 

 at Snow Hill in 1902—3, there exists a low-pressure area 

 in the Weddell Sea, furthest south in autumn and most 

 northerly in winter, but with a centre normally about 

 66° S. and 30° to 35° W. The continental origin of these 

 prevailing winds accounts largelv for the low temperatures 

 of the South Orkneys compared with their latitude. The 

 theimal gradient on the east of Graham Land is steep, 

 and this fact, in relation to the southward bending of the 

 isotherms about 40° W., is strong evidence for the exist- 

 ence of the northward projection of .Antarctica south of 

 the South Orkneys to about the Circle. Moreover, on no 

 other grounds is it possible to account for the verv low 

 temperatures that occur from time to time at Scotia Bay 

 witfi southerlv and south-easterlv winds. 



NAllVE WORKING OF COAL AXD IRON IN 

 CHINA. 



^X interesting illustrated article on the native working 

 of coal and iron in the province of Shansi, China, 

 appears in Engineering for December 2. In the Ping 

 Ting Chau districts the iron ore is of excellent quality. 

 The methods of extraction are decidedly primitive ; in the 

 old workings the ground is often found honeycombed with 

 small shafts, seldom more than 14 inches in diameter, and 

 usually just large enough to allow a man to go down. 

 The tools used consist of a native pick, a cast-iron 

 hammer, a wedge, and a sort of basket-shovel, the ore 

 being raised in the basket by a small wooden winch. The 

 climate is healthy, but work under such conditions is sure 

 to produce disease, and consumption is very prevalent. 

 During the summer the mines are shut down,' and all the 

 men become farmers until the close of the harvest season. 

 The southern district specialises in wrought-iron goods, 

 for example, spades, picks, nails, wrought-iron bars, and 

 general ironwork ; the northern district produces the larger 

 and rougher classes of goods, such as cast-iron pans and 

 sections of tyres for cart-wheels. Reduction of the ore 

 is conducted in roasting-kilns ; the broken-up ore is mixed I 

 with anthracite and charged into clay crucibles, which are | 

 heated in the kilns for about four days. The iron residue I 

 IS then treated in a foundry, where it is broken up and i 

 remelted in crucibles for the production of cast iron, or, 

 if wrought iron is being produced, bv melting in a | 

 crude furnace, hammering, and puddling. j 



The Ping Ting Chau district is one of the largest 

 NO. 2147, VOL. 85] 



anthracite coal beds of which there is any knowledge. 

 The natives get at the coal by adit or by shaft, as 

 may best suit the nature of the ground. Shafts var>- 

 from 6 to 8 feet in diameter, and from 60 to 300 

 feet in depth ; the thickness of the seam of coal varies 

 from 4 to 18 feet. During late years native mechanics 

 have been giving advice, with the result that collieries 

 are coming into existence in which the coal is hoisted 

 in baskets, and cow-hide bags are used for hauling 

 out accumulations of water. A Canton Chinaman 

 attempted to apply up-to-date methods to a mine just 

 outside the Ping Ting Chau area, and sank a shaft beside 

 the adit. He proposed to use a winch for winding up 

 the coal, but before this could be done w'ater was struck 

 and the mine flooded. Boilers and pumps were erected 

 by Chinese workmen, and the water was successfully 

 cleared out of the first level. Shortly after starting work 

 an explosion took place, and practically closed the shaft. 

 -At present the men are carrying the coal up the steps in 

 bags in an excessively high temperature due to the steam- 

 pipes, and the Cantonese has retired from the field. Pick, 

 hammer, and wedge are the only tools used. 



THE DYNAMICS OF A GOLF BALL^ 

 nPHERE are so many dynamical problems connected 

 with golf that a discussion of the whole of them 

 would occupy far more time than is at my disposal this 

 evening. I shall not attempt to deal with the many 

 important questions which arise when we consider the 

 impact of the club with the ball, but confine myself to 

 the consideration of the flight of the ball after it has left 

 the club. This problem is in any case a ver\' interesting 

 one ; it would be even more interesting if we could accept 

 the explanations of the behaviour of the ball given by 

 many contributors to the very voluminous literature which 

 has collected round the game ; if these were correct, I 

 should have to bring before you this evening a new 

 dynamics, and announce that matter, when made up into 

 golf balls, obeys laws of an entirely different character 

 from those governing its action when in any other 

 condition. 



If we could send off the ball from the cfub, as w^ 

 might from a catapult, without spin, its behaviour would 

 be regular, but uninteresting ; in the absence of wind its 

 path would keep in a vertical plane ; it would not deviate 



Fig. I. 



either to the right or to the left, and would fall to the 

 ground after a comparatively short carry. 



But a golf ball when it leaves the club is only in rare 

 cases devoid of spin, and it is spin which gives the interest, 

 variety, and vivacity to the flight of the ball. It is spin 

 which accounts for the behaviour of a sliced or pulled 

 ball, it is spin which makes the ball soar or " douk," or 

 execute those wild flourishes which give the impression 

 that the ball is endowed with an artistic temperament, and 

 performs these eccentricities as an acrobat might throw- 

 in an extra somersault or two for the fun of the thing. 

 This view, however, gives an entirely wrong impression 

 of the temperament of a golf ball, which is, in reality, the 

 most prosaic of things, knowing while in the air only one 

 rule of conduct, which it obeys with unintelligent con- 

 scientiousness, that of always following its nose. This 

 rule is the key to the behaviour of all balls when in the 

 air, whether they are golf balls, base balls, cricket balls, 

 or tennis balls. Let us, before entering into the reason 

 for this rule, trace. out some of its consequences. By the 

 nose of the ball we mean the point on the ball furthest in 

 front. Thus if, as in Fig. i, C the centre of the ball is 

 moving horizontally to the right, .A will be the nose of 

 the ball ; if it is moving horizontally to the left, B will 



I Discourse delivered at the Royal Institution on Friday. March 18, by 

 Sir J. J. Thomson, F.R.S. 



