KNOWLEDGE & SCIENTIFIC NEWS. 



fJlLY, 1905. 



All the elements have circulated in succession through 

 its structure, and then passed out again. First at the 

 highest temperatures came the heaviest and least vola- 

 tile elements, then as the temperature fell they gradu- 

 ally were eliminated and their places were filled by 

 analogous lighter and more volatile elements, until at 

 last living matter assumed its present composition. 

 But this replacement of denser by lighter elements is 

 now almost complete, for the principal elements already 

 present in living matter are carbon, nitrogen, oxygen, 

 and hydrogen. ^ And these it w ill be noticed are among 

 the very lightest non-metallic elements which, so far 

 as we know, exist. No lighter elements, then, can 

 replace those already present in the organism, and, 

 therefore, there can be no further very great alterations 

 in the temperature of living matter in the coming ages; 

 but the world is still cooling. Consequently, age by 

 an-e, century by century, the contrast between the tem- 

 perature of living matter and the temperature of the 

 surrounding medium is becoming more and more ac- 

 centuated, " and the difficulty of maintaining life is 

 steadilv increasing. I think, therefore, that .so far as 

 the surface of this earth is concerned, organic life is 

 entering into its last stage of evolution. 



University of Kiel, May. 1005 



A Ra^ised Beacch in 

 Anglesey. 



By G. H. I^.KVAN, F.R.S. 



In the island of .Anglesey, alxjut three miles north-east 

 of Beauniaiis and about one mile from Penmon, I came 

 across an interesting example of a raised beach, of 



are all common species, apparently. Many of the 

 specimens are, however, more or less worn and d'S- 

 coloured by iron oxide. Tlie boulder clay itself is of a 

 dark purple colour. 



The existence of these raised beaches is interesting 

 as showing the changes which have taken place in the 

 level of tlic earth. The section shown in the first photo- 



Fij(. I.— Section ol boulder Clay near Penman. AnKlt'.<ey 

 beach of sand overlyinf; It. 



which the accompanying photographs may give some 

 idea. It is situated in a small bay, and rests on the 

 top of a deposit of boulder clay at a height of some six 

 feet above the existing beach. At the eastern extremity 

 a stratum of broken shells occurs in the sand in several 

 places, and is well shown in the second of the two 

 photographs. In this shell deposit foraminifera arc 

 frequent; these are of large size and are mostly similar 

 to the recent forms occurring on the sands lx;low. They 



nf the Raised Bsach sh< 

 <;hcll Deposit. 



vhite streaks of 



graph h<is been exposed bv the action of the sea, which 

 at high tide reaches tlie foot of the bonkler clay which 

 it has exposed, and the identity of the foraminifera in 

 the shell deposit with the recent ones in the sand below 

 suggests that the changes of level have occurred in com- 

 paratively recent times. 



COR. DESPONDENCE. 



The Action of Wood on Photographic 

 Plates. 



To THE Editors of " Knowlicix;i:." 



Deak Sirs, — I have read with much interest the article on 

 the action of woods on photoRraphic plates in the dark, which 

 appears in this month's " Knowi.kdgi;," and, believins the 

 action due to the actual radio-activity of the wood, 1 was of 

 opinion that an emanation should I)e visible under proper con- 

 ditions, as is the ca.sc with tlie recognised radio-active sub- 

 stances— the intensity of the action of any radio-active 

 substance appearing to depend on the /nv/ncnn' of the atomic 

 disintegration rather than on the intensity of disintegration of 

 each individual atom. Hy using a very sensitive screen, I 

 have distinctly observed a homhardment from a piece of wood 

 fl used white frctwood), each individual scintillation being 

 about as bright as any I have observed from L'ranium, I'itcli- 

 blende, Polonium, or even Kadiuni, the great difference being 

 that, whereas from such substances the emanations pour forth 

 in such numbers as to light up the screen with countless 

 flashes, in the case of the wood they came singly or now and 

 again in twos and threes, with a considerable interval between 

 each. This would seem to account for the comparatively 

 feeble and slow action of woods, as it would of necessity take 

 considerable time before the cumulative effect would become 

 evident. 



I shall be very glad to know if scintillations from wood have 

 been observed before. 



\'ours very truly, 



Charles W. Raffetv. 



Strathmore, Streafham Common, S.W. 

 June 8tb, 1905. 



