June 9, 192 1] 



NATURE 



459 



are not large, and have attached to portions of their | 

 surfaces the very hard ferruginous matrix in which 

 they were embedded. The larger specimen is a 

 roughly shaped flint such as are found in some quan- 

 tity at Cromer. The yellow-stained surfaces are 

 typical, and exhibit the well-marked band of black 

 unchanged flint under the layer of cortex. The other 

 specimen is a small flake, with bulb of percussion, 

 radiating fissures, and eraillure, and shows similar 

 characteristics to the last-described flint, together 

 with a whitish coloration on the bulbar surface, which 

 is encroached upon extensively by the ochreous stain- 

 ing. This discovery establishes the fact of the occur- 

 rence at Sheringham of ochreous flints, comparable 

 in every respect with many found at Cromer, in situ 

 in the surface of the sub-Crag Stone Bed. It is estab- 

 lished also that artefacts of the same order are to be 

 found scattered among the large flints resting upon 

 the chalk, and exposed at low water immediately 

 opposite to the section in the cliff where the two 

 flints were found in situ. There would seem, there- 

 fore, to be little doubt that the Cromer specimens are 

 referable to the same horizon as those discovered at 

 Sheringham, namely, the basal layer of the Cromer 

 Forest Bed deposits. 



In my paper read before the Royal Anthropological 

 Institute I record the finding, at the Cromer site, of 

 a large, yellow-stained flake exhibiting a mass of 

 ferruginous "pan" material firmly adherent to a 

 portion of its surface. This ferruginous deposit 

 appears to be, in all respects, similar to that in which 

 the two Sheringham flints were embedded, and its 

 presence upon this flake supports the conclusion above 

 stated as to the geological age of the Cromer arte- 

 facts. J. Reid Moir. 



One House, Ipswich. 



The Physical Status of "Space." 



It does not appear from Dr. Jeffreys 's letter in 

 Nature of May 26, p. 394, that we are at variance 

 about anything really vital. What I do contend is this : 

 that, thanks to the searching character of the theory 

 of relativity, the time has come when it is profitable 

 to attempt a much-needed unification of fundamental 

 terms and conceptions, particularly in face of the 

 curious indiff^erence to such matters shown bv some 

 of those physicists who, with consummate skill, have 

 developed the differential equations representing the 

 natural forces. As the space of Nature is limited, 

 may I briefly, in a series of categories, amplify my 

 previous letters (April 7 and 21 and May 5), stating 

 the case for the extension theory suggestively, but in 

 no way dogmatically? 



(i) If you objectify the pure spatial co-ordinate 

 system of the mathematician you are of necessitv 

 dealing with attributes of some entity which, speaking 

 within the limitations of human experience, must be 

 supposed to answer to the designation "phvsical." I 

 press for no other use of the term "aether," and this 

 onlv as a safeguard against language suggestive of 

 nothingness or absolute emptiness. 



(2) The validity of the logical step (1) is supported 

 by the theory of relativity, particularlv the generalised 

 theory, which actually alTirms that' the only objec- 

 tive soace of human experience is physical space — out 

 of which basis of experience the mathematician con- 

 structs his subjective spaces and pure geometries (in 

 Dr. Jeffreys's sense of the word) representing various 

 ideal, or possible, universes. 



(3) The whole trend of twentieth-century physics 

 is to teach us to think in terms of energy, not in those 

 of matter. Matter is to be regarded as so much bound 

 energy, as symbolised, indeed, in Einstein's expres- 

 sion, mc', for the energy equivalent of mass. It 



NO. 2693, VOL. 107] 



seems legitimate, therefore, to infer that the attribute 

 of extension or extendedness ultimately belongs to 

 energy. 



(4) In the light of (i), (2), and (3), I submit that 

 a desirable unification of ideas can be effected, and 

 much confusion of thought avoided, if, instead of 

 regarding the universe as containing energy, we 

 regard it as betn^' energy. Let the physical universe 

 be defined as an evolutionary system of energy — that 

 is to say, as an extensive entity the very nature of 

 which is to express itself in changes and transforma- 

 tions (motions). This definition would render Comdr. 

 McHardy's artifice of "container" and "content" 

 (Nature, May 19, p. 360) unreal ; and I cannot see 

 that the distinction he makes is ontologically sound. 

 Furthermore, does not the picture of the universe 

 herewith presented throw into relief the necessary 

 association of time with space, and illustrate that 

 physical difference which leads us to regard time 

 as imaginary space? 



Finally, I would like to refer to the passage in Sir 

 Oliver Lodge's article (Nature, February 17, p. 800) 

 wherein he speaks of the necessity of "diving down 

 into the aether." The metaphor is literally pregnant 

 with meaning. It suggests, indeed, that when we 

 shall have peered into the untold depths of the mere 

 nameless thing — call it "space," "aether," "world," 

 "metric," "substratum" — which is the scene of 

 such momentous phenomena as light transmission 

 and gravitational potential, it will prove to be a verit- 

 able mine of energy and a truly formidable physical 

 reality. The great "aether" controversy seems now 

 nearly spent, and I think it could be settled to-day 

 if only the " non-aetherites " would frankly acknow- 

 ledge that the world-energy is continuous, and the 

 "aetherites " would think of their entity as an energy 

 continuum rather than as functioning as a kind of 

 independent luminiferous medium. 



L. C. W. Bonacina. 



May 29. 



The Colours of Primroses. 



In view of the turn given to this discussion by Dr. 

 Heslop Harrison's letter in Nature of May 19, it may 

 be worth while to state that in the Island of Sark 

 twenty-four years ago, in addition to an abundance of 

 normal primroses, there were also plenty of (a) white, 

 (b) pink, and (c) red flowers. Necessarily there can 

 have been no appreciable diflference of altitude. 



Occasionally we find red primroses hereabouts, but 

 my impression is — although I will not venture to 

 write positively — that they do not run to the deep red 

 of the Sark specimens. I remember finding one plant 

 on the edge of a field three miles east of Polperro at 

 an altitude of possibly 200 ft. or so. 



I feel fairly certain that I never saw any cowslips 

 in Sark — and I explored the island fairlv thoroughly. 



Frank H. Perrycoste. 



Higher Shute Cottage. Polperro, R.S.O., 

 Cornwall, May 27. 



Gold-coloured Teeth of Sheep. 



During the early part of the war the transport of 

 sheeo about the country districts was strictly regu- 

 lated so that a local butcher could state definitely in 

 which locality his meat had been fed. I noticed a 

 large number of sheep's teeth encrusted with bright 

 yellow tartar, identical in appearance with good 

 average bright non-arsenical iron pyrites. I was 

 assured that the sheep were fed upon Rye Marshes. 

 I have a number of these jaws, and I should be 

 pleased to send specimens to any museum interested 

 in them or to anyone who would undertake to publish 

 a full analysis and report upon the material. 



W. J. Lewis Abbott, 



