468 



NATURE 



[March 19. 1908 



semblances have anything to do with edibility, or the 

 reverse, and quotes Werner and Wcisniann to the effect 

 that they have not. One of the arguments used is that, 

 as a general rule, birds do not molest butterflies to any 

 great extent. The real explanation of the resemblances in 

 question will, in the author's opinion, be supplied by a 

 chemical theory of animal coloration. 



The third part of the Bergen's Museum Xarhog for 

 1907 contains a long article by Mr. C. F. Kolderup on 

 Scandinavian glaciation. At the period of greatest ex- 

 tension, it appears that the whole country was covered 

 with an ice-sheet moving in a westerly direction altogether 

 independent of local contours. When, however, the ice 

 began to diminish, the direction of movement gradually 

 became more and more dependent upon that of the valleys, 

 until finally the ice-sheet became resolved into a number 

 of large isolated glaciers filling the latter. Some geologists 

 admit only one great Ice age, and deny the intercalation 

 of a warm period between two such maxima, during which 

 the snow well-nigh disappeared from the Scandinavian 

 highlands. The evidence of the moraines and their 

 embedded shells is, however, in the author's opinion, amply 

 sufficient to justify belief in such an intercalation. Indeed, 

 the occurrence of several oscillations of level, with con- 

 comitant climatic changes, appears to be demonstrated. 



The Cotteswold Naturalists' Field Club has recently 

 issued in part i. of its sixteenth volume a paper by Dr. 

 C. G. Cullis and Mr. L. Richardson on the Old Red 

 Sandstone conglomerate of the Forest of Dean, in which 

 gold has undoubtedly been detected. A comparison with 

 the " banket " beds of the Rand is made, favourable to 

 the Forest of Dean so far as convenience in working goes ; 

 but the authors do not commit themselves as to the 

 average gold-contents of the British deposit. The same 

 part contains several papers on local geology, and a 

 finely illustrated account of species of the terebratuloid 

 genus Cincta, by Mr. S. S. Buckman. Terebratiila 

 numismalis here finds itself split up into a number of 

 species of Quenstedt's genus Cincta, which has priority 

 over several other names. 



The fourth part of vol. xx. of the Proceedings of the 

 Geologists' Association (January, igo8, price ^s.) consists 

 of a complete memoir by Dr. A. W. Rowe on the zones 

 of the White Chalk of the Isle of Wight, with an index 

 that includes all places and fossil species mentioned in 

 this and in the four memoirs that have preceded it. Mr. 

 C. D. Sherborn, who has often collaborated in this great 

 zonal work, supplies coloured maps on a large scale, and 

 the photographic illustrations are of extraordinary delicacy 

 and beauty. Dr. Rowe's twelve years' ' labour is here 

 brought worthily to a conclusion, and the necessity of 

 accurate zonal collection, if one would study any sequence 

 of fossil forms, is again set clearly before the reader. The 

 true course of invertebrate evolution can, after all, be 

 traced only by the painstaking methods of field observa- 

 tion inaugurated by William Smith at the close of the 

 eighteenth century. 



In the Bolletino of the Italian Seismological Society 

 Prof. Mario Baratta gives a detailed account of the 

 methods of construction adopted in re^building the 

 ■ Calabrian villages destroyed in the earthquake of 

 September 8, . 1905.. Frame buildings in- wood, filled in 

 with masonry or concrete, were largely adopted, and 

 armoured concrete for the more important buildings. The 

 report would have ■ been of greater interest had it con- 

 tamed an account of the behaviour of these erections in 

 NO. 2003, VOL. 77] 



the earthquake of October 23, 1907, which was said, in 

 the daily newspapers, to have destroyed some of the newlv 



built villages. 



We have received an advance copy of a paper bv 

 Dr. E. Oddone, to be published in the Bolletino della 

 Societd Sismologica Italiana, in which he makes the 

 suggestion, already put forward by Prof. Milne in the 

 last report of the British Association committee on 

 seismological investigations, regarding the possibility of 

 a causal connection between the two earthquakes on 

 August 16, 1906, which occurred within about thirty- 

 two minutes of each other, one in the northern Pacific, 

 the other in Chile. This interval being approximately 

 that which the wave motion of the second phase might 

 be expected to take in travelling from the origin of 

 the one earthquake to that of the other, it is suggested 

 that the arrival of these waves was the determining cause 

 of the time of occurrence of the Valparaiso earthquake. 

 An objection to the acceptance of this suggestion is the 

 uncertainty as to whether the second-phase waves are 

 not extinguished before reaching a distance of 120° from 

 the origin, that is to say, somewhat less than the distance 

 separating the origins of the two earthquakes in question. 



The Queensland Geological Survey has issued a Bulletin 

 (No. 216), by Mr. B. Dunstan, on the Great Fitzroy copper 

 and gold mine. Mount Chalmers, Rockhampton district. 

 The ore deposits, which have been known since i860, occur 

 in quartzite, which appears to be the result of the altera- 

 tion of limestone. It is estimated that there is about 

 145,000 tons of ore still available, containing 4J per cent, 

 of copper, 35 dwt. of gold per ton, and i ounce of silver 

 per ton. 



The weathering of coal forms the subject of an investi- 

 gation by Prof. S. W. Parr and Mr. N. D. Hamilton 

 (University of Illinois, Bulletin No. 17). They find that 

 an exudation of combustible gases from coal occurs from 

 the time of breaking out of the sample from the seam, 

 and that an absorption of oxygen accompanies the exuda- 

 tion. The process of deterioration is probably due to 

 oxidation of hydrogen or of hydrocarbons. It may also 

 be due to a simple loss of combustible gases and their 

 replacement by oxygen. The extent of the deterioration 

 varies with different coals, but the deterioration is prob- 

 ably most active during the first two or three weeks from 

 the taking of the sample. 



An interesting monograph on the rural highways of 

 Wisconsin, by ' Mr. W. O. Hotchkiss, has been issued 

 (Bulletin No. 18) by the Wisconsin Geological and Natural 

 History Survey. It covers 136 pages, and is illustrated 

 by sixteen plates. The improvement of the rural highways 

 of the State is a matter to which much attention has been 

 devoted, and the author supplies useful information re- 

 garding methods of road construction. He gives a 

 summary of the general principles of making roads, and 

 discusses the conditions obtaining in the State of 

 Wisconsin. In conclusion, he adds a digest of the laws 

 of those States where legislation in the matter of roads 

 has received most careful attention. 



In -.comparison with the thorough treatment of bridge 

 trusses by eminent writers, very little attention has been 

 devoted to roof trusses, and consequently the exhaustive 

 study described by Dr. N. Clifford Ricker in the University 

 of Illinois Bulletin, No. 16, forms a valuable addition to 

 technical literature. The investig-ation had for its original 

 object the derermination of a formula for the Weight of 

 roof trusses mor ) accur.it: :aan those in existence. Other 



