368 



NA TURE 



[February 15, 1900 



(3) Lecanockiton, ^askell. Two species. A very distinct 

 genus. 



The two following genera were thought peculiar to New 

 Zealand, but are now known from elsewhere : — 



(i) Eriochitoii, Maskell. The only species referred to this 

 genus from elsewhere than New Zealand is E. cajani, Maskell, 

 which is in reality a Ceroplastodes; but Mr. E. E. Green (in 

 litt.) tells me that he has just received a genuine Eriochilon 

 from Australia. 



(2) Solenophora, Maskell. This is now known from North 

 America and Ceylon. 



I have no doubt at all that all of the truly native species of 

 New Zealand Coccidae are strictly endemic. The only apparent 

 exception is that of Eriococcus mtiltispimis, Maskell, which is 

 said to occur in Australia on Acacia ; but the Australian form 

 was separated by Maskell as a distinct variety (var. laevigatus), 

 and is doubtless a valid species. T. D. A. Cockereli.. 



Mesilla Park, New Mexico, U.S.A., January 26. 



The Fitting of the Cycle to its Rider. 

 There is much interesting theory in your paper on the bicycle 

 fitted to the rider in crank and gear, by Mr. Crompton (p. 87). 

 But what is the practice ?. I agree with Mr. Crompton's theories, 

 if a slight modification be made. I think that the crank-length 

 should be proportional not only to a man's thigh-length, but to 

 the weight of a man's leg. The loss of power in a bicycle, as 

 soon as it travels fast, arises from the loss of momentum at each 

 up and down stroke of the leg according to the well-known 

 equation : — 



M = m.v. 



Where M 



momentum. 



mass. 



velocity. 



A slender-built man with a light, thin (even although long) 

 leg, can afford a higher value for v because his constant for vi 

 is low. 



Not so the strongly-built man with a high constant for in. 

 He must keep his velocity down, or M rises in value and there 

 is a loss of power at each stroke when travelling fast. 



Let 7iie give an illustration. A few days ago I was riding an 

 8" crank and 84 gear machine rather fast on a down grade. I 

 travelled swiftly but easily. In front of me was a low-geared 

 cyclist, his feet flying round at a high speed, the bicycle frame 

 quivering with the velocity of his strokes, the cyclist breathing 

 hard with his exertions. As I overhauled him I heard a 

 pedestrian remark against his scorching. Certainly he was 

 scorching in the sense of strongly exerting himself, but his 

 exertions were mainly expended in the lost momentum of each 

 stroke. The only remedy for this is a high gear. 



Admitting the advantage of a high gear, the necessity for long 

 cranks follows, otherwise the cyclist has not the power to face 

 hills, winds, or bad roads. Two inches increased crank-length 

 gives an enormously increased power of propulsion. I find that 

 with 8" cranks and 84 gear I can climb hills easier than with 

 an ordinary roadster, say with 6|" cranks and 64 gear. 



The increased comfort and safety on a bicycle fitted as Mr. 

 Crompton recommends are very remarkable and pleasing. The 

 ampler free motion does away with most leg-weariness and 

 saddle-soreness. The long, powerful cranks give one a com- 

 mand over the bicycle that is equally satisfactory up-hill or 

 down-hill. One gets over the ground with a long, easy swing. 

 Compared with the ordinary bicycle, it is like the outside edge 

 and the inside edge in skating ; or like rowing with sliding or 

 fixed seats. 



For track riding it seems possible that short cranks and high 

 gears may give the best return for the muscular power exertion 

 expended, since v is kept down by the high gear, and m 

 probably represents the limb of an active young athlete 

 weighing perhaps 10 stone. And, since there is little resistance 

 to be overcome, the long crank may represent an unnecessary 

 high lift of the leg. 



Conversely, the greatest advantage is to be derived from long 

 cranks and high gears in a hilly and difficult country, or where 

 the winds are strong, as here at the Cape, and when the rider 

 has a heavy, powerful leg. 



Long cranks and high gears necessitate an alteration to the 

 frame of the bicycle that is troublesome to makers. And hence, 



NO. I 58 I, VOL. 61] 



I suppose, the curious tabooing of the subject in the too-often 

 interested bicycle literature of the day. D. E. HuTCHiNS. 



Kolara, Kenilworth, nr. Cape Town, January 7, 



Telephones and Lightning Discharges. 



In Nature of February 8, Sir G. G. Stokes suggests an 

 arrangement for hearing a lightning flash in a telephone. To 

 hear the corresponding earth current, it is only necessary to put 

 a telephone in connection with the gas and water pipes of a 

 house. These pipes seem to suffice to entrap the corresponding 

 earth currents, which practically enable the listener to hear the 

 lightning. Flashes invisible in the daylight are quite noisy in 

 the telephone. A. R. Hunt. 



Southwood, Torquay. 



THE GEOGRAPHY OF EUROPE.^ 

 T7UROPE is undoubtedly the most refractory of the 

 ■*-' great divisions of the earth to get within the limits 

 of a geographical treatise. The mass and variety of data 

 of high scientific accuracy are so overwhelming that it is 

 impossible for any one man to make himself acquainted 

 with even a small fraction of the whole, and the com- 

 pilation of a book on Europe, even on the generous scale 

 which two volumes permits, cannot in the nature of the 

 case be much more than a compilation of earlier com- 

 pilations. In unskilled hands it could not fail to become 

 a heterogeneous collection of facts ; but Mr. Chisholm 

 has brought to bear experience and expert knowledge in 

 the choice and co-ordination of his material, and the result 

 is a credit to British geography. It shows a great amount 

 of reading amongst original, and sometimes not very ac- 

 cessible, works in many languages, which few compilers 

 would have considered it necessary to undertake in pre- 

 paring a volume in a popular series. Numerous references 

 are given throughout to the sources of information, and 

 we hope that the second volume will be furnished with a 

 bibliography of the best works dealing with Europe as a 

 whole, and with its larger regions. 



The plan of the " Compendium " has always been to 

 take the country rather than the continent as the unit, and 

 by doing so its scientific character has sufifered, because 

 the only possible element of unification has been ignored. 

 Mr. Chisholm has endeavoured, with considerable success, 

 to improve the plan of his volume by an excellent intro- 

 ductory chapter dealing with Europe in general, although 

 this, to our mind, is too short ; while the individual 

 countries appear to be described in disproportionate 

 detail. In a series obviously intended to convey inform- 

 ation rather than to inculcate geographical principles 

 this disproportion is, however, inevitable, and it is doubt- 

 less recognised more fully by the author than by the 

 critic. 



The guiding principle which has been kept in view 

 throughout all the descriptions of countries is that the 

 character of a country at the present time is due to the 

 influence of the physical structure of the land upon the 

 historical development of the nation. Hence a good 

 many geological and historical facts are mentioned ; but 

 they are mentioned, not as facts for their own sakes, but 

 as working causes accounting for the present adjustment 

 of peoples to lands. The application of this principle 

 has led Mr. Chisholm to commence his detailed descrip- 

 tion with Italy, which he treats with great fulness on 

 account of its historical importance. He gives to the 

 central Mediterranean peninsula nearly twice as much 

 space as to Russia or France, and a third more than to the 

 German empire. Interesting as Italy is, and vast as was 

 its influence on all Europe, we confess that we should 



1 Stanford's "Compendium of Geography and Travel (New Issue), 

 Europe. Vol. I. The Countries of the Mainland (excluding the North- 

 west)." By Geo. G. Chisholm, M.A., B.Sc. Maps and Illustrations. Pp. 

 XX -t- 736. (London: Edward Stanford, 1899.) 



