594 



NATURE 



[Oct. 17, 1889 



I would particularly call attention to the third and fourth 

 measurements, as also to the last two, and venture to think that 

 no one could entertain the trustworthiness of data that involve 

 such great changes in cranial capacity in such short spaces of 

 time. To what, then, are these differences due? Partly, of 

 course, to unavoidable errors of observation. This, however, I 

 think is only a small portion of the differences. The main 

 difference is, I believe, due to other causes. Anyone who has 

 seen the instruments will recognize that they are far too rough 

 and imperfect to measure small differences with any degree of 

 accuracy, and yet it is on differences as small as one-tenth of an 

 inch that Mr. Gallon's calculations are based. 



I admit it is quite possible that, even after elimination of the 

 eiTors due to experimental causes and to the imperfection of 

 the instrument, the figures would still be somewhat variable. 

 These variations may, however, be readily explained, without 

 the assumption of any improbable head-growth. The amount 

 of hair on the head must considerably influence the measure- 

 ments, and, according as it is long or short at the time of mea- 

 surement, so will the figures show an increase or a decrease. I 

 have tested this, and proved it to be the case. On August 30 

 (my hair not being very long, having been cut two and a half 

 weeks previously) my head was measured, the figures being as 

 follows : — 



5-8, 7-4, 5-6 = 240-35. 



I then had my hair cut fairly short, and was measured again ; 

 the figures then read — 



57. 7 "4. 5'5 = 231-99. 



Again, the scalp being, as is well known, very vascular, any 

 change in the fulness of its vessels must materially affect the 

 thickness of the scalp, and so influence the measurements, and 

 so any cause producing either increased blood-flow or hindering 

 the return of blood from the scalp, will have some effect on the 

 measurements. 



Several other similar explanations of supposed head-growth 

 might be given, but I think the m.easurements I have given will 

 suffice to show the uselessness of the measurements for calculat- 

 ing head-growth, and, further, that such differences as actually 

 do exist can be readily explained without having recourse to any 

 such improbable assumption as the further growth of the head 

 after nineteen years of ae^e, and without involving the unintel- 

 ligible statement that the head of a "poll" man grows more 

 than the head of an honour man. This would necessitate the 

 supposition that a "poll " man, by his three years' study (?) at 

 Cambridge, profits more than an honour man ! Such an hypothesis 

 would need more scientific proof than has been given. 



Trinity College, Cambridge, September 3. H. J. P. 



Glories. 



Coloured rings are often seen surrounding the shadow of 

 the spectator's head when the sun is shining on a fog of water 

 particles. They are known by various names, such as glories, 

 anthelia, Ulloa's rings, &c. Can any of your readers mform 

 me if they can also be seen when the fog is frozen ? I should 

 also be glad of accurate accounts of their colour and angular 

 dimensions. I have read those given by Scoresby (Kaemtz, 

 "Meteorology," translated by Walker) ; Flammarion (Glaisher's 

 "Travels in the Air") ; Abercromby {Phil. Mag., January 

 1887); and Mohn (Nature, February 1888). 



James C. McConnel. 



Hotel Buol, Davos, Switzerland, 



Fine Slow-mov.'ng Meteor. 



On September 25, at 8h. 5m., I saw a bright first-magnitude 

 meteor amongst the stars of Aquarius. It moved very slowly 

 to the east, and, after a duration of about 13 seconds, dis- 

 appeared at the point R. A. 11°, Deck -f 8°. lis place of first 

 appearance was near R. A. 332°, Deck - 7i°, so that the length 

 of its observed path was about 42°. The nucleus was followed 

 by a thick train of sparks, and at the end it divided into two parts. 

 This meteor was observed at Oxford by Mr. W. PI. Robinson, 

 of the Radcliffe Observatory. He writes : — "This evening a 

 fine meteor was seen slowly moving between the constellations 

 Aquarius and Pegasus, at 8h. 5|m. G.M.T. It was first seen at 

 K.A. 33C°, N.P.b. 88°, disappearing near R.A. 352°, N.P.D. 

 82° ; duration, 3 or 4 seconds." A comparison of these obser- 

 vations shows that the radiant point was probably in R.A. 244^, 



Deck - 22°, and that the meteor, when first seen, was at a 

 height of 46 miles over a point in the English Channel 20 miles 

 south of the Isle of Wight. It disappeared near Staplehurst, ini 

 Kent, at the same height. Length of path, 100 miles. At 

 Oxford, the early part of the meteor's flight was not seen. The 

 Bristol observer watched the meteor through 91 miles of its 

 course, and the duration of 13 seconds would give a velocity of 

 7 miles per second. At Oxford, 35 miles of the terminal section 

 of the flight was seen in 3 or 4 seconds, which gives a velocity 

 of ID miles per second. 



Further observations of this body would be valuable to cor- 

 roborate these results. The meteor was an exceptional one, 

 both as regards its slow speed and the position of its radiant 

 point. No meteor-shower has hitherto been recognized at this 

 epoch in the region of Scorpio. Isolated slow-moving meteors 

 of this description are of great value as giving us indications of 

 feeble systems not otherwise discoverable, and as allowing good 

 determinations to be made of their heights and velocities. 



Bristol, October 4. W. F. Denning. 



A Brilliant Meteor. 



At 7h. 6m. ± p.m. G.M.T., on October 10, a brilliant meteor 

 was observed here, about 10° south-west of a Pegasi, and travel- 

 ling from thence to near Jupiter, being apparently three times 

 the size and brilliancy of that planet. Its colour was of a 

 bluish-white, and it possessed a fine train, disappearing after six 

 seconds, having burst into a number of pieces. W. Hugo. 



Kew Observatory, Richmond. 



The Shining Night-Clouds— An Appeal for 

 Ob: ervations. 



The following is the substance of an appeal for observations^ 

 made by Herr O. Jesse in the spring. The time of year in 

 which the clouds appear in these latitudes has now elapsed ; I 

 have seen no sign of them this summer, either in this country 

 or while travelling in the Alps. But as Mr. D. J. Rowan sa\% 

 them (see Nature, June 13, p. 151) it is very desirable that 

 they should be looked for in all parts of the world. I see Mr. 

 Le Conte assumes (October 3, p. 544) that Mr. Rowan is correct 

 in calling these clouds self-luminous — which conclusion I agree 

 with Herr Jesse in considering highly improbable. 



Sunderland, October 12. T. W. Backhouse. 



The time of year has again arrived when the lustrous silvery 

 clouds, which have appeared annually in June and July from 

 1885 to 1888, may be expected to again become visible to- 

 observers throughout Europe. 



These clouds are not only of high meteorological interest, but 

 may be of an almost greater astronomical on^, for, from their 

 so decidedly pronounced periodicity, joined to their extra- 

 ordinary height, it may perhaps be inferred that they are of 

 extra-terrestrial origin. 



As there is entire lack of previous record of these clouds,, 

 and they may disappear soon for an indefinite period, I would 

 earnestly ask for such early observations as may be likely to- 

 determine their origin, nature, and periodic motion. Spectro- 

 scopic examination of their light would be valuable. Prof. 

 Galle and others have considered that the clouds in question 

 are phosphorescent, but this is very improbable, and I hold they 

 are scarcely, if at all, visible unless the sun shines directly upon 

 their substance. On this assumption, their height in 1885 was 

 found to be from 49 to 54 kilometres ; but, by photographic 

 observations in 1888, it came out as great as 75 kilometres. 



Prof. Kohlrausch advances the opinion that these clouds have 

 in some way been formed by the eruption of Krakata~o, although 

 they were not generally seen until nearly two years after that 

 event. From this hypothesis I suggest that they may be caused 

 by the condensation of gases from that volcano, and that the 

 process of condensation occupied the intervening time. One 

 observer, however, states that he saw them in 1884. 



NOTES. 



We deeply regret to have to record the death of James Pres- 

 cott Joule, one of the greatest men of the age. He died on 

 Friday last at "^is residence at Sale, near Manchester. 



