August 27, 1896] 



NA TURE 



391 



Till 5.50 the sun remained partially eclipsed. Thus we ob- 

 served the sun on our steamer 0/oden, while returning to Bodo. 

 But who could imagine our surprise, and the increase in our 

 gratitude for the splendid conditions in which we had seen the 

 eclipse, when, twenty minutes after totality was over, we saw 

 the sky everywhere, and especially also at the sun's side, covered 

 M ith hca\y clouds ! It was as if these clouds had been caused 

 by some cooling effect of the eclipse. A. Brester, Jk. 



Delft, Holland, August 23. 



Air Temperature during the Solar Eclipse. 



Some observations of air temperature, which I was able to 

 make at Vadsii during the solar eclipse un .\ugust 9, are perhaps 

 worthy of being put on record. I observed on the plateau or 

 flat-topped hill north of the town of N'adsb, a few minutes' walk 

 beyond Prof. Copeland's station, and at the height of 400 feet 

 above the sea, by aneroid. None of the astronomical observers 

 occupied quite such a high position. It was chosen in order to 

 escape the disturbing effect of air-currents on the hill-side 

 sloping to the fjord. The thermometer was provided with a 

 small bulb, and hung from the tripod of a 3-inch telescope, the 

 bulb being about 18 inches from the ground. No special pre- 

 cautions were taken to shield it from the sun's rays ; un- 

 fortunately, they were not necessary. A light northerly breeze 

 was blowing, and the sky was heavily clouded. 



Speaking roughly, the eclipse began at 4, was total at 5, and 

 was over by 6 o'clock. At 4.8 and at 4. 18 the temperature was 

 44 0° F. ; at 4.23, it was43-5° ; at 4.28 and 4.33, 43-2°. From 

 4.35 to 4.43 the sun was shining brigluly, and the temperature 

 rose to 43'3° ; at 4.53 and 4.59, glimpses of the sun were caught 

 before and after totality. The temperature from 4.48 to 4. 58 

 was steady at 43'0° ; at 5.0, it had dropped to 42'r ; from 5.3 

 to 5. 13 it stood at 42 ■3\ By 5.33 it had risen to 43 '8°, and at 

 5.48, when I ceased observing, to45'o'. 



The suddenness of the fall at, or rather immediately after, 

 totality is very marked, the depression amounting altogether to 

 I -9' F. from the commencement of the eclipse, and the sub- 

 sequent rise being equal to 29° F. to the end of the eclipse. 



I Savile Row, W. , August 24. Hugh Robert Mill. 



The Position of Science at Oxford. 



Vour correspondent " W, E. P." shows a curious ability for 

 injuring his own side. He says that "Oxford collectively has 

 done her best to remove any inferiority she may have had in the 

 past" in respect of her scientific school, and further, "it would 

 be difficult to name a body better qualified to decide what is a 

 good general education than Convocation itself." And yet the 

 whole tone of his letter is a practical confession that Oxford has 

 failed in her best attempt, and that her view of general educa- 

 tion has resulted in a ]iractical failure to forward an essential 

 branch of general education. The fact is Oxford's best is bad, 

 and her ideal education is one-sided. The most serious cause of 

 complaint of modern society against the old universities is that 

 they have so controlled the education of the wealthy classes of 

 the community that the landed and professional classes have 

 been educated apart from the commercial and industrial classes 

 to the very great injury of both. One might as well consult a 

 committee of clergy as to the best education for a doctor, as 

 advise with university dons as to the best education for the 

 general community. The influence of a Pagan civilisation has 

 created in them an ideal of life founded on contemplative learn- 

 ing, rather than on a Christian benevolent activity. 



Geo. Fras. Fitzgerald. 



Trinity College, Dublin, August 19. 



On the Notation of Terrestrial Magnetic Quantities. 



\'v the International Meteorological Congress to be held in 

 Paris, a number of questions of special interest to magneticians 

 have been proposed for discussion, among which is the follow- 

 ing : — " The same notation should be generally employed, //for 

 horizontal force, X for the northern component, Y for the 

 western component, Z for the vertical force, and V for the 

 potential.'" As the need of some uniform notation has been made 

 apparent to me in connection with the journal Terrestrial Mag- 

 netism, I have been paying this matter some attention with the 



NO. 1400, VOL. 54] 



view of obtaining a concise and logical system for adoption in 

 that journal. 



The principle upon which I proceed is to take the first letter 

 of a word dc-signating a particular quantity, if at the saine time 

 it conforms with typographic requirements, such, for example, 

 as declination, which is common to several languages. In this 

 way I have thus far obtained the following : D for declination, 

 / for inclination, H for horizontal component of force, V for 

 vertical component, Fiot total force. Upon examination it will 

 be found that these letters .stand for words derived, in almost all 

 cases, originally from the Latin and Greek languages, and with 

 but insignificant variations in spelling, common to several of the 

 main modern languages. 



The Germans will be asked to yield a point with regard to 

 F,^ but this, as will be seen below, will be made up to theni in 

 the adoption of G for magnetic potential. F taken from the 

 Latin Tis, or / from intensitas, or D from the Greek word 

 Siivaiuis, would not do for force, as they are already taken. Nor 

 would T from tolus or P from irnr answer, since the former is 

 frequently used for time of vibration, and so in fact is the letl-er 

 /", which stands besides for the first deflection coefficient. As 

 I hope to be able to find a satisfactory notation for all the 

 principal magnetic quantities, I am keeping this matter con- 

 stantly in mind in adopting any particular letter. The English 

 and French have force, and I have, therefore, adopted /' for 

 total force. As it is frequently the custom to designate angular 

 quantities by Greek letters, I should have preferred, had it been 

 possible, to adopt S and t instead of D and /, but the Greek t 

 is a very unsatisfactory letter from a typographical standpoint. 

 Moreover, if found desirable later on, the small letters rfand i 

 or 6 and t can be reserved for the variations on the mean of day 

 and on the mean of year respectively. 



I think it very much to be deplored if Z, as above proposed, 

 be universally adopted to designate the vertical force. It should 

 not be forgotten that the Gaussian mode of resolving the mag- 

 netic force into northerly component {X), westerly component 

 ( \), and vertical coinponent (Z), applies to a /yea/ system of co- 

 ordinates, not to a fixed system, as the layman might naturally 

 suppose — a fact which is even apparently forgotten at times by 

 magneticians. The mean values of the.se components for a 

 complete circuit of the earth along a parallel of latitude can, in 

 consequence, no more be physically interpreted than the mean 

 H, for example. I am, therefore, opposed to adopting for the 

 vertical force a letter which in no way gives evidence of the exact 

 quantity for which it stands. V, on the other hand, is logically 

 connected with H, and at the same time implies that the direc- 

 tion of the quantity that it syinbolises is local, the direction of 

 the vertical or plumb-line varying from point to point. 



For the same reasons I am not in favour of adopting X for 

 northerly component, and Y for westerly component. Let 

 authors choose this method of notation, if they prefer it ; but in 

 a system suggested for universal adoption, it would seem to me 

 that N and //' would more satisfactorily meet the requirements, 

 clearly indicating to the eye as they do the local character of the 

 system of coordinates employed. 



As a letter to designate the earth's magnetic potential, I be- 

 lieve none more fitting could be adopted than G, after Gauss, 

 the author of this function. Gauss himself used V, but this letter 

 is not sufficiently characteristic ; it is used to designate many 

 other functions in mathematical physics ; and there would, 

 moreover, be a conflict in our system, since V seems the most 

 logical letter to designate the vertical force. L. A. Bauer. 



Linden, Montgomery County, Maryland, August 10. 



On "Hullite." 



The authors of a paper just published in the Transact io)ts ai 

 the Royal Irish Academy, which is certain to be widely read, 

 have dealt at length with the material called " hullite," urging 

 that it is, in reality, " a hydrous glass of low specific gravity." 



This paper was read on June 10, 1S95, but a " note added in 

 press " concludes as follows : — 



"An abstract of this paper was published in Nature of 

 June 27, 1895 ; since then I have received, by the kindness of 

 Prof. Cole, a paper by him on ' hullite ' [reference given, Proc. 

 Belfast Nat. Field Club, 1894-5, p. l]. It contains an interest- 

 ing risitini of the literature of the subject, and describes, quite 

 independently, the occurrence of ' hullite ' as ' a true ground- 



1 The initial letter of the Ge 

 designate the moment of inertia, : 



