March 2, 1916I 



NATURE 



Science and the State. 



In reference to the nxent memorandum signed bv 

 thirty-six eminent pien of science on the neglect of 

 science in our national organisation, it maj- be of 

 some interest to your readers to be reminded of the 

 paragraph on a similar topic written by Thomson in 

 his '"History of Chemistry," which api^eared in 1831, 

 or more than three-quarters of a century ago : — 



"What Minister in Great Britain ever attempted to 

 cherish the sciences, or to reward those who cultivate 

 them with success? If we except Mr. Montague, who 

 procured the place of master of the Mint for Sir Isaac 

 Newton, I know of no one. While in even- other 

 nation in Europe science is directlv promoted, and 

 considerable sums are appropriated for its cultivation 

 and for the support of a certain number of individuals 

 who have shown themselves capable of extending its 

 boundaries, not a single farthing has been devoted to 

 any such purpose in Great Britain. Science has been 

 left entirely to itself; and whatever has been done 

 by way of promoting it has been performed bv the 

 unaided exertions of private individuals." 



The above statement is not literally true of the pre- 

 sent day; but the same spirit of indifference still exists. 



J. B. COHEX. 



The Universitv, Leeds. 



ally in Terrestrial Magnetism and Atmospheric Elec- 

 tricity, where a series of reports are in the press. 

 Kristiania, February 15. Carl Stor.mer. 



Ground Rainbows. 



My observations of ground rainbows are here de- 

 scribed in the hope of learning whether the pheno- 

 menon is well known. I can find no reference to it, 

 and no information as to how the gossamer, which 



3>l«lCTt«»t 



•>s(m 



Altitudes of Aurorae. 



Tn Nature of August ;, 1913 (vol. xci., p. 584), a 

 Tt account was given of my auroral expedition of 

 i V I think, therefore, that the accompanying pre- 



^3C0Km. 



200 



' i^^^K j'^^ of aurjra borealis seen from Bossekop during the spring of 1913. Each calculated altitude is 

 markf d by a dot and the several hundred simultaneous photographs of aurora from the stations— Bossekop 

 and btore Korsnes— <mutual distance 27^ kilometres) gave about 250c determinations of height, which are seen 



liminar)- result of the determination of altitude (Fig. i) 

 will interest your readers. More details will soon be 

 published in the Comptes rendus of the Paris Academv 

 ot Sciences, in the Astrophysical Journal, and especi'- 

 XO. 2418, VOL. 97] 



causes the rainbow, and seems to be a kind of spider- 

 web, comes to be spread over so large an area. 



The ground rainbow observed occurred about ii.o 

 a.m. on October 14, 1915. A cricket field of about 



two acres was covered with 

 a thick la\er of gossamer 

 which the early morning 

 mist had loaded with mil- 

 lions of glittering beads of 

 water. As one walked over 

 the ground a rainbow of 

 about the brilliancy of a 

 good secondan,' bow moved 

 over the grass — stretching 

 from one's feet in the 

 direction away from the 

 sun in a sweeping curve 

 with two arms. . The ex- 

 planation is obvious on the 

 ordinary theory of primary 

 rainbows. 



Those rays will enter the 

 eye which fall on the drops 

 in the direction of the thick 

 circle, A R, R, B S A 



(Fig. i). But the raindrops 

 were all on the ground, 

 and so what the eye saw 

 was the underneath part, 

 A S B, of the rainbow 

 circle — that is, the rays 

 which lie on the under sur- 

 face of the cone, E .v y 

 (Fig. 2). The rainbow is 

 therefore the trace of the 

 cone, E.xy, on the ground 

 plane. It follows at once 

 that the form of this trace 

 will depend on the angle 

 of elevation of the sun ; 

 when the sun is in 

 the zenith the curve is a 

 circle, when the angle of elevation is between 90° and 

 42° it is an ellipse, when 42° a parabola, and when 

 below 42° a hyperbola. Some of mv pupils measured 

 the elevation, by finding the height and length of 



