246 



NA TURE 



[August 26, 1909 



placed in Brassolis. In Kirby's Catalogue of 

 Diurnal Lejiidoptera and Supplement (1871 and 1877) 

 we find eight genera of Brassolidae and fifty-four 

 species, while Dr. Stichel now enumerates eleven 

 genera and seventy-five species, in addition to a very 

 considerable number of forms treated for the present 

 as subspecies. 



Dr. Stichel describes the species at great length, 

 adding tables of the genera, species, and subspecies. 

 The synonymy of the genera and species is very 

 fully given, and the excellent text-illustrations in- 

 clude the neuration of one species of each genus, and 

 also the markings of the wings of a large number 

 of species, both surfaces being usually figured. De- 

 scriptions are also given of the eggs, larvae and 

 pupae of the insects, as far as known at present, and 

 the range of each species is also indicated. On 

 pp. 3 and 4 we find general information on the habits 

 of the butterflies, and should have liked more detail 

 under the various species ; but we presume that there 

 was either no room, or the available information on 

 the subject was too meagre to be worth giving, except 

 in a general manner. W. F. K. 



The Volcanic Origin of Coal and Modern Geological 

 Theories: a Pica for Lessening Demands on Geo- 

 1-^gical Time; and for Furtlier Separating the Life 

 Jlistorics of the Aqueous and ]'olLanic Formations. 

 Py Col. A. T. Fraser (late R.E.). Pp. 21. 

 (London : R. Banks and Sons, 1909.) 



Th2 old Wernerians used to account for volcanic 

 action by the supposed combustion of coal within the 

 e.Trth's crust, but tlie author of this pamphlet turns 

 the tables upon them by making the volcanoes pro- 

 duce the coal ! The way in which this feat is per- 

 formed is as follows : — ^first by pointing out that in 

 the sides of the active volcano Gedeh in Java the 

 tuffs are seen to be well stratified, and look, at a 

 distance, like old red sandstone ; then the mud de- 

 posits ejected by the eruption of Tarawera in New 

 Zealand are also stratified. Next, we have somewhat 

 of a leap in the advance of the argument. The Java 

 f^xperjence showed, though coal was absent, another 

 way in which it (coal) might originate; namely, 

 being rained down in a shower of bitumen alter- 

 natelv with sandstones, shales, &c. In support of 

 this view we are told that a visit to " the Quarries of 

 Carrara and Parnassus " show that " maVble is a 

 volcanic rock," "ejected, accompanied by high-pres- 

 sure steam, from a fissure and showered down." 

 We must leave our author with the coal and marble, 

 and not attempt to follow his leading among geo- 

 logical theories, old and new. We fear, jiideing 

 from books advertised on a fly-leaf at the end of the 

 one before us, that the author has been so much 

 occupied with psychical research, occult powers of 

 Eastern nations and the religions of the world, that 

 he has not found time for even a very little ele- 

 mentary chemistry. 



Cassell's " Xaturc" Copies (]Vild Floivers). .Aids to 

 Nature Study, Brushwork, and Drawing. In 

 twelve packets. (London : Cassell and Co., Ltd., 

 n.d.) Price 6d. net per packet. 



Each of these packets of drawing copies contains ten 

 examples of pictures of wild flowers executed in 

 colours on stout plate paper. Though the best plan 

 IS to have wild flowers drawn from actual specimens, 

 these copies mav serve a useful purpose in town 

 schools, where it is very difiicult or impossible to 

 procure the plants themselves ; in anv case they will 

 add variety to the art work, and familiarise children 

 •with the beauty of common wild flowers. 

 NO. 207S, VOL. 81] 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part 0/ N.iTURE. 

 No notice is taken of anonymous communications.] 



August Meteoric Shower. 



I HAVE summarised in a form which may be convenient 

 for comparison some of the results of Perseid observations 

 this year. The differences in some cases are remarkable, 

 and sufficiently prove that to arrive at definite conclusions 

 respecting the character of a shower a large number of 

 materials should be consulted and averaged. Weather con- 

 ditions are dissimilar, the places of observation are not 

 equally well situated (certain positions in towns are much 

 affected bv artificial light), and there are other causes 

 which must introduce discordances. Though comparatively 

 few Perseids were observed at Bristol and Meltham on 

 .August 10, they were fairly numerous at Blaina and 

 .-\ntwerp, and on the night of August 12, when a rich 

 display of brilliant meteors was remarked at Bristol, there 

 was no striking exhibition witnessed at several other 

 places. 



Kesults of Perseid Observations, iQoq. 



Apparently few determinations of the radiant have been 

 made, but so many values have been found for this at 

 previous returns tliat further estimates are not much 

 needed. Photographic inijiressions of the trails would be 

 of essential value as giving, not only a very exact position 

 for the radiant, but as indicating its character and the 

 extent of its diffusion. W. F. Denning. 



The Ringing of House-bells without Apparent Cause. 



Until I read the two letters in Nature of July 22 and 

 -August 12 I had no idea that the ringing of house-bells 

 without apparent cause was so fascinating a subject, as 

 my own experience of it has been rather prosaic. One of 

 my bells occasionally rings when no one is in the room, 

 but it is entirely due to bad workmanship. The strength 

 of the spring which draws the wire back after it has been 

 pulled is only about equal to the friction of the wires, 

 and the result is that, though it generally draws the wire 

 back immediately after it has been pulled, yet it sometimes 

 fails to do so at the time ; but after some time, it m.ay be 

 hours, owing to some change in the conditions, it succeeds 

 in drawing back the wire, when the bell again rings when 

 no one is touching it. The bell thus rings once when it 

 is pulled, and a second time when the spring succeeds in 

 drawing back the wire. 



The electrical explanation of any mysterious ring- 



