April I, 1884] 



NA TURE 



525 



velop" them. But when these webs do begin to appear, they 

 would naturally be small, and would appear to be rudimentary ; 

 so that in this stage they would exactly represent the " wholly 

 untenable doctrine " which Mr. Romanes denounces as an "in- 

 version of Mr. Darwin's teaching." Asa matter of fact rudi- 

 mentary organs on the way to future use can be identified in the 

 aquatic larva; of the Ephemerre. 



The truth evidently is that the theory of the origin of species 

 by transmutation, involves of neces ity a constant succession of 

 structures which are on the wane, and another succession of 

 structures which are on the stocks. Whether any particular 

 structure now dissociated from use, belongs to the one or to the 

 other class, is a question of evidence from associated facts. Kut 

 the idea of some structures being on the rise, is an idea insepar- 

 able from the theory of evolution as taught by Darwin. Fully 

 persuaded, as I am, that there is a very large amount of truth in 

 that theory, I am equally persuaded that, as yet understood, it 

 is incompetent to solve the most important phenomena of 

 creation. In the hands of Mr. Romanes, and of many others, 

 it is almost reduced to the repetition of mere verbal formula;, 

 under which anything and everything may be brought, only 1-e- 

 cause they are empty of any definite meaning. The derivation 

 of instinct from experience is an excellent example. 



Argym. 



Rain-band Spectroscopy Attacked Again 



I HAVE just had the honour of receiving a copy of an essay 

 read before the riiilosophical Society, Washington, D.C., and 

 printed in the American yoiirnal of Science for the present 

 month, wherein I read on p. 209: — 



" The results of observations with the rain-band spectroscope 

 are now called in ques'iDU by many prominent meteorologists. 

 In fact the unsatisfactory nature of the evidence may be easily 

 shown to the satisfaction of any one possessing an instrument. 

 If the spectroscope is fir.st turned to the sky in any direction and 

 afterward to a white w all fifty feet distant, it will be found im- 

 possible to distinguish between the appearance of the rain-band 

 as shown by the w hole atmosphere and by the layer fifty feet 

 thick." 



If this be the most damaging accusation that can be brought 

 up, after the memorable correspondence in both Nature 

 and the Times during the autumn of 1882, there is hope of con- 

 verting "the prominent meteorologists" yet. 



For cannot they, as well as other men, see, that a white wall 

 close to an observer in daylight, necessarily reflects the light, and 

 with that, the spectrum, of the sky which is illumining it, solar 

 lines and telluric lines and all ! 



Or if the worthy gentlemen still doubt, let them illumine their 

 white wall at midnight w'ith policemen's lanterns or Swan's 

 incandecent lamps ; and then I can promise them they will get 

 out of it and the "layer of air fifty feet thick" in front of it, 

 neither solar nor telluric spectrum lines in any kind of weather. 



C. PiAZzi Smyth 



IS, Royal Terrace, Edinburgh, March 25 



The Remarkable Sunsets 

 In reply to inquiries sent out by me to Prof. John Milne of 

 the University of Tokio, Japan, I am informed that no volcanic 

 dust was known to have fallen in Japan during or after the 

 Krakatoa eruption. He forwards, however, the following ex- 

 tracts, which may be of interest to your readers. 



John W. Judd 

 Science Schools, South Kensington, S.W. 



"Japan Gazette, Friday, Sc/t. 21, 1S83. — Shortlyafter noon on 

 August 30 the sun seemed to diminish in power, and a uniform 

 yellow gray haze spread over the sky, gradually becoming more 

 pronounced, and at two hours before sunset its rays were merged 

 into a faint halo emerging from a globe of light no larger than 

 the full moon. On Frid.iy, August 31, at 8 a.m., sun the same. 

 At II a.m. looked like full moon ; cnild easily observe it with 

 the naked eye. At intervals, faint clouds like puffs of smoke 

 crossed the sun's face ; they were enormously high. No wind ; 

 atmosphere dull and heavy, and neither heat nor light. Septem- 

 ber I, the same. On Sunday, sun became as usual, and haze 

 passed away. The Japanese were alarmed, and expected earth- 

 quakes." 



Prof. Milne adds the not ; : " If this were due to Krakatoa, 



almost 2500 miles away, the speed of the dust must have been 

 thirty miles an hour, assuming the date of the eruption to be 

 12 p.m. on August 26." 



The coloration of the sky in the neighbourhood of the sun, 

 described by " B. W. S." in Nature of March 27 (p. 503), has 

 been repeatedly observed by myself from Februaiy 20 (or there- 

 abouts) up to March 24. My fir.;t record of it is on February 

 24, wlien I describe it as a "rusty-red" tint. On other occa- 

 sions I have called it "rusty brown" and "pale brick-red." 

 Sometimes it has liad a purplish or roseate hue. It has been 

 chiefly seen between 10° and 20° from the sun (at a rough esti- 

 mate), and only when the sun was hidden by a detached cloud. 

 Frequently, when the sky has been clear, the intervention of a 

 house or other object between the observer and the sun has 

 revealed the presence of a hazy metallic-looking glare arourd the 

 sun — an appearance not perhaps very remarkable in itself, but 

 remarkable by its frequent repetition. 



If, as seems probable, the explanation of these phenomena is 

 to be fuund in a gradual subsidence of the reflecting matter which 

 occasioned the remarkable sunsets, it will be well for ob-ervers 

 to be prepared with suitable arrangements for catching what may 

 fall. I have myself had in operation for some time past two 

 separate devices for this purpose, the one intended for dry 

 weather, the other for rain. In dry weather I expose a tray 

 containing a number of glass .slides, each with a drop of glycerine 

 in a shallow cell, ready to be covered with this glass after suffi- 

 cient exposure. For rain I use a 12-inch bell-glass supported in 

 an inverted position on a three-legged stand, the legs partly 

 buried in the earth, and the height such as to raise the receiving 

 area of the glass to 30 inches above the soil. A rain-gauge is 

 less suitable for the purpose, and experience has shown me the 

 necessity of guarding .against the introduction of particles of soil 

 by the rebound of hailstones. 



An investigation of this kind is difficult in the neighbourhood 

 of a city, and it is much to be wished that observers living in 

 isolated situatims may be induced to undertake it. 



It may be worth recording that on February 24, after an 

 interval of several weeks, we had a striking recurrence of the 

 sunset phenomena so often described. It was not perhaps the 

 very finest example, but, as regards the primary glow, there had 

 been nothing equal to it since January 12. Unfortunately I 

 was not able to watch for the secondary glow. It is singular 

 that at both the beginning and end of this series of phenomena 

 there should have been outlying examples separated by some 

 weeks from the rest. The first of the peculi.ir sunsets observed 

 in this country appears to have been on November 9. Then I 

 find no record until November 24. From th.at date (allowing 

 for interruption by weather) they may perhaps be considered to 

 have been continuous until February 2, becoming scarcely notice- 

 able tow.ards the last. Then, finally, after an entire absence of 

 fully three weeks there comes, on February 24, a sunset which 

 must be ranked amongst the finest of the series. 



Clifton, March 31 George F. Burder 



Referring to the "decidedly unusual //«/5 tinge" occa- 

 sionally observed around the sun " when shining in a somewhat 

 hazy sky, the colour being broui;ht out v ilh great distinctness 

 if a light cloud happens to be pa- sing across it " {see Nature, 

 March 27, p. 503), I wruld mention that, under the described 

 circumstances, I have often noticed last winter a peculiar colour, 

 to which I would apply the French term -dure d\ngnon (onion 

 skin), used to describe certain kinds of champagne. I offer this 

 suggestion, as 1 know the value of precise and happily chosen 

 terms, especially in the difficult mailer of the terminology of 

 colours. O. S. 



Heidelberg, Germany, March 29 



Thread-twisting 

 The habit of thread-twisting with the palm of the hand on 

 the thigh is one which may be seen in every part of India at the 

 present day ; we think it can hardly be termed a rude method, 

 or a savage art, though the Mohammedans, w hose ancestors came 

 not so very long .ago from Central Asia, practise it as much as, or 

 even more than, the Hindoos. As " J. S." observes in Nature 

 of March 20 (p. 478), it may be one of the survivals from a 

 barb.arous period which we have lost since the introduction of 

 machinery. Perhaps some of your correspondents may be able 



