August 23, 1894] 



NA TURE 



399 



him in this, but he means Malone) to assume that re- 

 ference is intended to the notion that each age was 

 dominated by one of the seven planets. However, he 

 shows a close correspondence between many expressions 

 in the T€t/ju'3i/3^os and in Roman writers under the 

 empire, Manillas, Vitruvius, and Pliny. 



The work concludes with an excursus on the date of 

 the aaTpc^iiyovfiiva of Petosiris and Nechepso, which had 

 been referred to the first century before, but Dr. Boll 

 gives reasons for placing in the first century after, the 

 Christian era. W. T. L. 



LETTERS TO THE EDITOR. 



[The Editor dots not hold himselj reipomtbh for opinions ex. 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejectea 

 manuscripts intended for this or any other part o/ Nature. 

 No notice is taken of anonymous communications.l 



Platinum Resistance-Thermometers. 



At the meeting of the British Association, just coming to an 

 end, it was pointed out to the Committee of Section A, by Mr. 

 E. H. Griffiths, that the general adoption of the method of 

 thermometry, founded on the variation of the electric resistance 

 of platinum with temperature, that has been worked out by 

 Prof. Callendar and himself, is seriously hindered by the 

 existence of a report presented to the Belfast meeting of the 

 Association in 1S74 (British Association Report, 1874, pp. 242- 

 249)1 by a Committee "appointed for the purpose of testing the 

 new pyrometer of Mr. Siemens." As I was secretary of this 

 Committee and drafted the report, and as all the experiments 

 were made either by myself or under my direction, I was 

 desired by the Committee of Section A to ask you to allow me 

 to slate in the columns of Nature (what is indeed obvious to 

 anyone who refers to the 1874 report) that the tests carried out 

 by the Committee of 1874, and the conclusions arrived at by 

 them, had reference solely to the pyrometers supplied to them 

 for examination by Messrs. Siemens Brothers, and that they 

 have consequently no bearing on the question of the 'rust- 

 worthiness or accuracy of the platinum resistance-thermometers 

 of the kind devised by Messrs. Griffiths and Callendar. 



August 15. G. Carey Foster. 



International Courtesy. 



! LEARN from a speech of Prof Ludwig Boltzmann, in Sec- 

 tion A to-day, and also from some Englishmen well acquainted 

 with German Universities, that I have unintentionally offended 

 the physical philosophers of Germany by one or perhaps two 

 ill-considered and hasty expressions employed in the first edition 

 of my " Modern Views of Electricity." 



These remarks do not occur in the second edition, but mere 

 silent withdrawal of them does not convey the information that 

 I desire to convey to my illustrious leaders and confrlres in the 

 foreign scientific world. I therefore request you to permit me 

 space to make the following amende. 



When I said tliat the four great names in connection with our 

 partial knowledge of the nature of electricity were (excluding 

 living persons) Kranklin, Cavendish, Faraday, and Maxwell, X 

 ought to have interpolated the adjective British before the word 

 "names," in order to avoid entering upon much larger questions 

 than were at all appropriate to the expository course of lectures 

 on which the book " Modern Views " was based. 



The second remark was this: — When emphasising the great 

 achievements of Hertz, in my lecture at the Royal Institution 

 on "The Discharge of a Leyden Jar" (reprinted as appendix 

 to same book), I spoke of him as "no ordinary German." 

 Literally of course it is true, but it may easily be interpreted in 

 a discourteous sense. It was, however, less widely known then 

 than it is now that Hertz was a German savant of the highest 



NO. 1295, vol. 50] 



type, and this fact I wanted to express ; but if the proverbial 

 odiousness of implied comparisons had only happened to strike 

 me, I would certainly have altered the mode of expression 

 before any reprints of my lecture were made. 



Prof. Boltzmann seems to think that the context to this 

 remark indicates that some rancour was felt in this country 

 tha'. the fruits of Maxwell's theory should have been reaped by 

 a German. That, if true, would be a serious accusation, but I 

 can assure him that it is conspicuously untrue. To an English- 

 man my words would not even convey the impression. I 

 honestly think that at the present era no trace of international 

 jealousy exists among English and Irish physicists. 



August 14. Oliver J. Lodge. 



A Remarkable Meteor, 



While at Pasadena, eight miles north-east of Los Angeles, 

 California, on July 27, a few minutes before half-past seven, 

 the writer had his attention suddenly drawn towards the 

 north-western horizon by a bright flash of light as of the burst- 

 ing of a meteor ; but on keeping his gaze fixed on the point 

 where this flash appeared, he was surprised still more to 

 see that instead of disappearing, as usually happens with meteors 

 when they explode, there remained a very luminous figure, 

 somewhat of the shape of the new moon but with more wavy 

 outlines, and of an intense whiteness, something as of an electric 

 light, in well defined relief against the pale golden glow of the 

 sky. The whole time during which this luminosity was 

 visible was something over twenty minutes, and it had 

 ceased to be visible at eight minutes before eight. The 

 crescent shape was not maintained more than about three 

 minutes, then it took the appearance of a luminous vapour 

 or cloud rising vertically for a little distance and then bending off 

 sharply to the left in almost an horizontal line, but not showing 

 any tendency to dissipate or grow thinner at the end farthest 

 from the point of origin. As time went on, the whole figure 

 became more wavy in outline, but persistently remained fixed in 

 the same part of the sky. The bottom, the point of origin, was 

 slightly brighter than the rest of the figure, and a little reddish 

 in colour, and the underside of the arm outstretched to the left 

 was brighter than the upper side. It was clearly beyond, and 

 in no wise connected with, the Sierra .San Gabriel, which cut 

 the sky with a dark, well-defined lune under the luminous 

 figure. AH who were watching it perceived that it was 

 no common cloud ; the north-western sky was cloudless and free 

 from haze, and no cloud in the west at such an hour can shine 

 with this sort of light, which indeed had more the lustre of 

 white flame. 



The cloud seemed unbroken so long as it was visible at all. 

 It would be idle to speculate beforehand on the exact locality 

 of this outburst, since no accurate estimate of its distance could 

 be formed at the time ; but the direction, as nearly as the writer 

 could judge by reference to the pole star, was about north 35° 

 to 40' west, which, projected on a map of the State, gives 

 about the direction of Tehachipi Peak from Pasadena. 



The direction in which the meteor was seen to ex- 

 plode, as stated by other observers all the way from the 

 Needles in the south-eastern part of the State to Lodi and 

 Oakland in the central counties, that is to say, from points 

 five hundred miles apart, en.ibles one, by projecting those bear- 

 ings which are reported in most detail, viz., Fresno, whence 

 it seemed a little north of west ; Keeler, whence it also seemed 

 a little north of west and directly beyind Mount Whitney ; 

 Tracy, whence it seemed to be in the south-east ; and Pasadena, 

 whence it seemed, as above stated, to limit the spot over which 

 it exploded to some point in the north-western part of Fresno 

 county or the south-western part of Merced county, both being 

 in the San Joaquin Valley, and 250 to 300 miles from Pasadena. 

 With much greater diffidence the writer would estimate its 

 angular height above the true horizon at not to exceed 3°. 



Los Angeles, July 29, Edward W'essos. 



[From newspaper cuttings sent with the foregoing it appears 

 that the meteor was seen at the Lick Observatory at 7h. 35m., 

 and that the explosion was heard at 7h. 361m. .\x Benicia the 

 meteor was extremely brilliant for a moment, and then dis- 

 appeared in a column of white vapour about two degrees long. 

 This cloud remained visible for a quarter of an hour. At 

 Fresno and at Redlands the luminous stream was visible for 

 twenty minutes. An observer at Tracy says that a loud report, 

 resembling a clap of thunder, was heard in the south-east. 



