July 14, 1904] 



NA TURE 



249 



drifting finally into armed expeditions and the reduc- 

 tion of native strong-holds. 



American pluck and endurance are fully tested in 

 these little frontier wars, which afford opportunities 

 for the practical training of soldiers such as are rapidly 

 disappearing on the borderland of the continental Red 

 Indian. Cholera appears to be their deadliest foe in 

 the field, allied to certain forms of local disease the 

 e.xact nature of which is not readily recognisable from 

 Mr. Landor's description. The author has no high 

 <i|>inion of modern medical science. The Filipinos (he 

 icUs us) are not yet ;oolish enough to believe in the 

 mosquito theory for malaria. Nevertheless, they build 

 their houses on piles so as to raise them sufficiently 

 above the humid atmosphere of the ground level to 

 insure a free current of air. Nor does he himself believe 

 in the efficacy of boiling water in order to render it 

 free from germs and choleraic impurities. Pre- 

 cautions of any sort, indeed, do not appeal to his 

 ■>|)irit of chivalrous adventure. When climbing 

 precipices " I did not use ropes or other such 

 nonsensical .\lpinistic devices; my rule has always 

 been to use common sense and avoid all accidents." 

 This certainly is an e.xcellent rule (if not entirely 

 original), and one much to be commended to the 

 .\lpine ("lub. But combined with a proud disregard 

 for such conventional appliances and precautions as 

 usually become more valued by the geographical 

 explorer the farther his experiences e.xtend, Mr. Landor 

 undoubtedly possesses that great facultv of human 

 sympathy which enables him to deal with all classes 

 of people, and to obtain the confidence (even the co- 

 operation) of the aboriginal natives in branches of 

 research which must have appeared to them exceed- 

 ingly strange and suspicious. It is most difficult to 

 persuade the brawny independent savage of the jungle 

 to permit himself to be handled and measured, to have 

 calipers applied to his head, and a minute examination 

 made of all the features which nature has given him, 

 for a purpose which is absolutely unintelligible to his 

 limited understanding. 



But Mr. Landor succeeded admirablv, and the result 

 is undoubtedly a valuable contribution to anthropo- 

 loirical science, although the constant repetition of 

 tables of measurement might very well have been dis- 

 pensed with in a book which (regarded as a popular 

 work) is already too long. 



The multitude of the islands forming the Philippine 

 group, and the excessive variety of detail which 

 permeates them, the differentiation between the manv 

 tribes which inhabit them, and even the enumeration 

 of their extraordinarily abundant v-egetable products, 

 become confusing after a while, and it is a relief to 

 turn to the story of pure adventure, and the occasional 

 interludes of graphic description, which is what the 

 world looks for from .Mr. Landor's pen. Doubtless it 

 is .Mr. Landor's intention to pose seriouslv as a scien- 

 tific observer, and there is Quite enoueh in the book 

 to justify the assumption; but it might have been 

 better had he made a little wider separation between 

 that which belongs to the realm of statistical detail 

 and that which is narrative of personal adventure. 



T. H. H. 



.1 PROBABLE CAUSE OF THE YEARLY 



WlRLiTION OF MAGNETIC STORMS AND 



AIROR.E. 



T \ a previous number of this Journal (vol. Ixvii. 



p. 377) an account was given of the verv close 



relationship which seemed to e.xist between the epochs 



of the occurrence of prominences in the polar regions 



of the sun and Ellis's " great " magnetic disturbances. 



In a later number (vol. Ixviii. p. 257) il was shown 



NO. '81 I, VOL. 70] 



that the presence of these polar prominences 

 synchronised also with the appearances of large 

 " polar " coronal streamers as seen during total solar 

 eclipses. Disturbances near the solar poles seemed to 

 play such an important role both in solar and terrestrial 

 changes that an inquiry was made to find out whether 

 anv effect is felt on the earth when either of these solar 

 poles is turned towards the earth during the course 

 of the year. The result of such an investigation, 

 recentiv communicated by Sir Norman Lockyer and 

 the writer to the Royal Society, will here be briefly 

 stated. 



During the course of a year the south pole of the 

 sun is most turned towards the earth in the beginning 

 of March, and the north pole most towards the earth 

 in the beginning of September. .-\t the two inter- 

 mediate epochs, in the beginning of June and 

 December, neither pole is turned towards or aw-ay 

 from the earth, but occupies an intermediate position. 

 Hence we sec that the equinoxes occur in the same 



DIRECTION 



EARTH'S POLES ij. 

 SUN 



Fk,. 1.— Curves showing the relalionship between the positions of the earth's 

 poles in rehuion to the sun, the sun's poles with regard to the e^rth, and 

 the frequency of magnetic disturbances and auro.a: throughout a year. 



months as those in which one or other of the solar 

 poles is turned towards the earth, while the neutral 

 positions of the solar poles in relation to the earth 

 occur in the same months as the solstices. 



If, therefore, these solar polar regions are capable 

 of disturbing the magnetic and electric conditions on 

 the earth, then, when they are most directed to her 

 at the equinoxes, the greatest effects during a year 

 should be recorded, and when they are lea^t directed 

 the effects should be at a minimum. 



With regard to the facts about the v.iriation of 

 magnetic disturbances and aurorae, Mr. Ellis has 

 shown that the curves of ■ frequency of magnetic dis- 

 turbances at Greenwich and Paris are very similar, 

 " showing maxima at or near the equinoxes, and 

 minima at or near the solstices." These also, he 

 further points out, are similar, with regard to the 

 epochs of maxima, to the curve representing the 



