HARD WICKE 'S SCIENCE- G OS SIP. 



forwarded by him to Mr. Curties, F.R.M.S. Mr. 

 Richter, in his paper, well described it as "a little 

 insect porcupine." 



For secure preservation it should be mounted in 

 balsam, without pressure ; but to obtain fine results 

 for the purpose of drawing, it is better prepared dry, 

 in such a method, as to be capable of being seen 

 under any circumstances — from beneath with the 

 paraboloid, and from above (after removing the 

 covering glass) with reflected light from the side 

 speculum. Under these conditions of double or 

 simultaneous illumination, the finest points of character 

 and especially of colour are revealed. 



The preliminary sketch was made with the aid of 

 the camera lucida ; but as the objective used {to bring 

 out the full details) rendered it impossible to get the 

 whole of the subject into one circular field of view, 

 the difficulty was overcome, by shifting the stage 

 adjustments and fitting the parts, for the ultimate 

 drawing from direct observation. 



Crouch End. 



BLOOD-RED SUNSETS AND THEIR 

 AFTER-GLOW. 



ATMOSPHERICAL phenomena appear lately to 

 have been in a very unsettled state. " Nature " 

 has been occupied with letters relating to a "green 

 sun " in India, and the first explanation was that 

 somehow it was due to the Javan earthquake. The 

 last week in November and far into December will 

 long be memorable for the "blood-red sunsets." 

 They reached their maximum of beauty in the Metro- 

 polis, where the fog and smoke, unbearable usually, 

 are excellent auxiliaries to sunset effects. All over 

 the country for nearly a month, the most gorgeous 

 sunsets and sunrises were noted, followed by after- 

 glows equal to the most striking displays of the 

 aurora borealis. 



Both the scientific journals and public newspapers 

 have contained an unusual amount of correspon- 

 dence respecting the exceptional brilliance and 

 persistence of the evening after-glow, and the cor- 

 responding phenomenon at day dawn.. It is well 

 known that the conditions necessary for the produc- 

 tion of this display are most favourable in northerly 

 climates, owing, it is believed, to the suspension of 

 particles of frozen vapour in the air, or other strata 

 of varying density against which the rays of the sun 

 can strike, and from which they can be reflected. 

 The "Lancet" asks whether we may not expect a 

 winter of unusual severity as a possible sequel to 

 such splendid atmospheric displays. Mr. G. J. 

 Symons, the distinguished meteorologist, in a letter 

 to the "Times," suggested that these brilliant after- 

 glows, together with the blue suns and green suns 

 which have been described in various parts of the 

 world, are due to the rise of vapours and volcanic dust 



from the Java eruptions into the higher regions of 

 the atmosphere, thus affording the necessary condi- 

 tions. He points out that as early as September i6th 

 Mr. J. P. O'Reilly, of Dublin, called attention to 

 the quantity of gases and vapour emitted during 

 eruptions, to their probable relation to the total 

 quantity of matter emitted, and to their exerting 

 some effect upon the atmosphere. From that time 

 to the present, all kinds of strange and exceptionally 

 brilliant and chromatic effects have occurred in 

 India, Ceylon, the Cape, Venezuela, Barbadoes, 

 New Zealand, Australia, and other places, as well as 

 throughout Great Britain, and Mr. Symons thinks 

 that the enormous discharge of vapours and volcanic 

 matter into the atmosphere from the eruptions in Java 

 may be reasonably held to off"er some explanation. 



Mrs. Somerville, in her " Physical Geography," 

 shows that the fog and lurid light of 1783 were due to 

 the great eruption of Skaptar, in Iceland. For months 

 after the outbreak the island was obscured by the 

 enormous quantity of fine dust borne aloft in clouds of 

 vapour. This volcanic dust was carried by winds 

 over England and Northern Europe, and caused the 

 atmospheric effects described by Cowper ("Task," 

 book ii.) and by Gilbert White. 



Mr. F. A. Rollo-Russell points out that the vesi- 

 cular nature of pumice, each particle consisting of a 

 small bubble of glass, would allow it, after being 

 shot up by the eruption to an enormous height, to 

 be carried without precipitation to all quarters of 

 the glol)e, and at the altitude attained it would be 

 far removed from the action of vapour and weather. 

 Nothing like this diffused atmospheric glow after 

 dark, and one or two hours before sunrise, has been 

 observed before, and a singular effect must have its 

 origin in a singular cause. On December ist and 

 2nd, the glow, which was of an amber cblour, 

 did not become bright until about an hour after 

 sunset, and was partially obscured by clouds. The 

 phenomenon was mistaken for aurora borealis in 

 France and elsewhere, but it yet requires a name of 

 its own. 



During the south-westerly gale which raged over 

 England and Wales on December nth, the blood- 

 red sunset was again splendidly visible in several 

 places, and the after-glow lasted for two hours. The 

 phenomenon appears to have been universal, and was 

 witnessed in both hemispheres, the same general 

 effects being noticeable. Consequently Mr. Symons' 

 explanation, so far, appears the most probable. 



Mr. Norman Lockyer, F.R.S., has contributed a 

 veiy interesting and important "paper to the " Times," 

 in which he expresses his belief, that the enormous 

 volumes of fine volcanic dust emitted by the Java 

 earthqukes and eruptions have been carried into the 

 upper air, and that in the course of their progress 

 across and above the earth, the reflection upon them 

 of the sun's setting rays has produced the briUiant 

 phenomena of which so many accounts have been 



