November 27, 1919] 



NATURE 



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cheBte fauna of this country. A few local names are 

 in use, such as dew-worm, brandling, lob-worm, and 

 cockspur, but these are as valueless for scientific pur- 

 poses as cuckoo-flower or bachelor's buttons would be 

 to a botanist. 



It will be some time before my volume on British 

 earthworms is published by the Ray Society. In the 

 meantime, will not some publisher undertake to issue a 

 small popular handbook of British worms, with illus- 

 trations, at a shilling? We have about fifty earth- 

 worms in this country, but only a dozen or so are by 

 anv means common, and it would be very easy for 

 our working naturalists to get a grip of the subject, 

 and thereby render immense service to a branch of 

 science which is of the utmost practical value. 

 Though 1 have written a large number of articles 

 on our .Annelids during the past thirty years, there is 

 nothing on the subject which is available in a popular 

 and handv form for would-be students, and in this 

 matter such a handbook is sadly overdue. 



Mav I venture once more to appeal to readers of 

 N.-\TfRE for specimens of luminous worms or othi r 

 creatures, as well as for rare, unusual, or abnorm.d 

 forms, that would merit attention in my Ray Society 

 monograph? Hilderic Friknd. 



Cathay, Solihull, November 6. 



The Doubly Refracting Structure of Silica Glass. 



In an interesting letter on the above subject in 

 N.WURE of October 23 Lord Rayleigh mentions that, 

 when used with accurately crossed Nicols, "a circular 

 disc of optical quality silica showed a spiral struc- 

 ture." Upon reading this letter I was reminded of a 

 verv interesting colour effect I saw several years ago 

 in fused quartz which had been acted on by the rays 

 from radium. .As is well known, crystalline quartz 

 assumes a uniform yellowish-brown or brownish-red 

 colour when "rayed" by the rays of radio-active 

 substances ; the formation of coloured streaks and of 

 patches similar to the markings of marble has also 

 been ob.served. On the other hand, fused quartz 

 generallv assumes a uniform brownish-violet colour 

 when exposed to radium rays. 



In his work preparatory to the determination of the 

 atomic weight of radium, Honig.schmid (Wien. her.. 

 CX.X., 1617, 191 1) used fused quartz evaporating basins 

 for recrystallising large quantities of radium chloride, 

 and these afterwartls showed a remarkable spiral 

 coloration. Radiating from the centre of each basin 

 was a series of spiral-shaped streaks of a dark violet 

 colour, which continued in many cases almost to the 

 top of the basin. Their upper extremity would un- 

 doubtedly be limited by the height to which the radium 

 chloride solution had occupied the vessel. The space 

 between the streaks showed little or no coloration. 

 .\s is usual in such ca'ses, the coloration disappeared 

 on heating the dishes in a Bunsen flame, a brilliant 

 bluish-violet luminescence being produced. 



It has generallv been assumed that the conditions in 

 the quartz which give rise to these "streaks" are 

 connected with the mode of manufacture of such 

 . vessels, and I believe the above colouring effects may 

 be of interest in view of Lord Rayleigh's interesting 

 .observation of the "optical heterogeneity" of silica 

 (glass. RoRKRT W. Lawson. 



The Phvsics Laboratory, 

 Sheffield University, 

 October s'- 



The Antiquity of Man. 



In the altogether excellent jubilee number of Natirk 

 (No. 2610, vol. civ.) there is, I notice, a short pap-r 

 entitled "The .Antiquity of Man" contributed by Dr. 



NO. 2613, VOL. 104] 



A. Smith Woodward. We are told in this paper 

 (p. 212) that "as discoveries progress it becomes 

 increasingly clear that true man, of the family 

 HominidcB, cannot [the italics are mine] be earlier 

 than Late Pliocene or the dawn of the Pleistocene." 

 We learn also that " so long ago as 1880 " Sir 

 William Boyd Dawkins, " for other reasons," came to 

 the same conclusion. 



.As vour readers are doubtless aware, the question 

 as to when man first appeared upon this planet has 

 always been of what may be termed the " vexed " 

 order, and generally regarded as unsettled. 



But though it may be the opinion of Dr. Smith 

 Woodward and of Sir William Boyd Dawkins 

 that "true man" cannot be of a. greater 

 antiquity than " Late Pliocene or the dawn of 

 the Pleistocene," it does not necessarily follow that 

 such an opinion is correct. The chief evidence upon 

 which the idea of the great antiquity of the human 

 race is based — evidence not mentioned in Dr. Smith 

 Woodward's article — is that afforded by the various 

 implements of flint and other rocks which have been 

 found embedded in certain Pliocene and Pleistocene 

 strata. Those humanly fashioned stones are com- 

 paratively numerous, and afford evidence of a more 

 complete' type than is provided by the "few fragments 

 of apes and man " which have hitherto been recovered 

 from ancient deposits. 



In view also of certain discoveries made in Suffolk 

 since igof) (described by Sir Ray Lankester and by 

 myself), and the results "of the excavations carried out 

 during the last twelve months in the Red Crag at 

 Foxhall, near Ipswich, I would venture to regard it 

 as highly probable that a type of man capable of 

 flaking flints in a clearly dexterous manner was present 

 in that part of the country not later than Middle 

 Pliocene times, - and possibly even earlier. Further, 

 these discoveries have demonstrated that, as would be 

 expected, these Mid-Pliocene individuals were preceded 

 by an earlier race or races of people who fashioned 

 their flints in a less skilful manner. But whether 

 these ancient fiint-flakers were "true" men or not I 

 am quite unable to sav. I should imagine, however, 

 that, judging from the kind of implements found, 

 thev' had attained to a status far above that of any 

 known ape. 



It is clear, then, that Dr. Smith Woodward's views, 

 as expressed in the jubilee number of N.aturk, upon 

 the antiquity of man do not coincide with those of 

 many of us who have made a study of early flint 

 implements. Moreover, the fact that such widely 

 divergent views upon this question are possible shows 

 the urgent need for further research, especially as the 

 present palaeontological evidence, upon which Dr. 

 Smith Woodward's opinions are founded, is, from its 

 verv nature, largely negative in character. 



J. Rf.id Moir. 



I THINK our present knowledge of the farts and 

 principles of palaeontology justifies the statement I 

 made. I intentionally omitted all reference to chipped 

 flints because I regard them as inconclusive eviden'ce. 



A. Smith Woodward. 



W 



WESTERN TURKESTAN. 



ESTERN TURKESTAN has been, for all 

 practical purposes, a closed land ever since 

 the final subjugation of the Turkomans by Sko- 

 beleff in 1880. Political conditions made it diffi- 

 cult for Europeans, and particularly for British, 

 to travel in the province. It was reserved for the 



