2l6 



NA TURE 



[August* 1 2, 1922 



Equation (2) means physically that the energy 

 difference kv is transferred from the atom to the 

 ether, where it resides as the energy of vibration of a 

 shell of ether, the radius of the shell expanding 

 with the velocity of light. Baly's second assumption 

 gives us the thickness of this shell. If the time 

 occupied in releasing the energy hv = A n+n — A„ be 

 k seconds, the number of wave-lengths generated is 

 kv. The thickness of the shell is therefore 



kv\ = kc. 



(7) 



which is constant and independent of frequency. 



Again, as the energy radiated is hv, and the number 

 of pulses equal to kv, the energy radiated per period 

 of vibration, or the energy in a shell of ether of the 

 thickness of one wave-length, is equal to 



i-=7= constant (8) 



kv k ' ' 



It is interesting to note that Baly's third assum- 

 tion, viz. 



h.-K, (9) 



makes the constants of equations (5) and (6) identical 

 for all atoms. For similar identity of the constant 

 of equation (8) it is necessary that, like /;, 



AccE (10) 



Satyendra Ray. 

 University College, London, W.C.i, 

 July 12. 



Extraction of Radiolaria from Oozes. 



I have recently obtained some deep-sea radiolarian 

 ooze from which I am endeavouring to extract the 

 shells with as little damage to them as possible. I 

 have tried the method advocated by Mr. Martm J. 

 Cole, in which disintegration is brought about by 

 prolonged boiling with a strong solution of sodium 

 carbonate, and also another method in which the 

 deposit is boiled with a saturated solution of sodium 

 acetate, cooled till crystallisation has taken place, 

 and then warmed till the mass has melted and 

 boiled again, repeating this process several times. 

 Although the smaller shells are successfully extracted 

 by this means, I come across many large fragments 

 of beautiful silicious formation, evidently the result 

 of the breaking up of larger and more delicate ones. 



I wonder if any readers of Nature could tell me 

 of a better method of extraction, whereby I may 

 obtain these larger ones entire ? If so, I shall be 

 extremely grateful. Evidently the above methods 

 of extraction are too drastic for these more delicate 

 forms. H. L. Thomas. 



Dyffryn Vicarage, Neath, S. Wales, 

 July 10, 1922. 



Mr. Thomas does not state whether his radiolarian 

 oozes are recent or fossil. The two methods which 

 he has employed are primarily intended for the dis- 

 integration of fossil earths such as the Barbados 

 material, and as they depend for their efficiency on the 

 disruptive action of crystallisation and the solvent 

 action of alkalis on silica, they are necessarily more 

 drastic in their action than is necessary for the 

 cleaning of recent deposits. 



Recent radiolarian deposits differ greatly in their 

 nature, according to the rate of deposition and the 

 depth. In some cases where the ooze has been 

 rapidly formed it requires no further treatment than 

 washing under a gentle stream of water on sieves 

 of various grades. This method has the additional 

 advantage of preserving the calcareous organisms, 

 which are retained on the coarser sieves with the 



NO. 2/54, VOL. I IO] 



larger Radiolaria. The smaller forms pass through 

 all sieves with the diatoms, etc., and may be separated 

 from the muddy water by elutriation and decanting. 

 If it is not desired to retain the calcareous forms the 

 material may be treated with nitric acid. The 

 general treatment may be found in Cross and Cole's 

 " Modern Microscopy," pp. 257-261 (Bailliere, Tindall 

 and Cox, 1922). 



Some recent radiolarian oozes have come under my 

 notice in which the rate of deposition has been so 

 slow that the material is already in a subfossil 

 condition, laminated in structure, and with the 

 organisms more or less infiltrated with manganese. 

 Such oozes are refractory ; they contain scarcely any 

 calcareous matter and so are resistant to acid treat- 

 ment. They can be broken down only bv repeated 

 treatment with hot soda solution alternated with 

 drying, and such methods are necessarily destructive 

 to delicate organic structures like the larger forms of 

 Radiolaria. Arthur Earland. 



An Attempt to Influence the Rate of Radioactive 

 ^[Disintegration by Use of P enetrating Radiation. ^ 



Investigations carried out by Ellis (Proc.\Roy. 

 Soc. 101, 1, 1922) at the Cavendish laboratory lead 

 to the conclusion that quantum dynamics probably 

 apply to- the nucleus of the atom and lend support 

 to the assumption that the emission of 7-rays from 

 the nucleus precedes the disintegration process. This 

 highly interesting hypothesis suggested an investiga- 

 tion whether the rate of radioactive disintegration 

 can be influenced by exposing the substance to the 

 action of penetrating radiation. Could the nucleus 

 be induced to take up a 7-ray impulse supplied by 

 an exterior source, it would mean a change in its 

 stability and so most probably in the rate of its dis- 

 integration. As 7-ray source about 800 mg. radium 

 element were used, and experiments carried out with 

 uranium in radioactive equilibrium with UX . and 

 with radium D in equilibrium with radium E. 



(a) Experiments with Uranium. — The thin-walled 

 glass tube containing the radium preparation was 

 placed for six weeks on a 2 mm. thick layer of uranium 

 oxide of 1 cm. 2 surface ; by this arrangement practi- 

 cally all kinds of 7-rays emitted by the radium and 

 all ji-rays except the very soft ones reached the 

 uranium preparation. By measuring the /3-radiation 

 of the uranium X in equilibrium with uranium before 

 and after the experiment no change amounting to 

 more than o-i per cent, in the activity could be de- 

 tected. 



Now, from the uranium quantity used, about 

 15,000 atoms break down in one second, so we can 

 conclude from this negative result that the natural 

 disintegration of our uranium preparation was cer- 

 tainlv not followed by an artificial disintegration of 

 more than 15 atoms per second. The radium pre- 

 paration employed emits about io 11 7-ray quanta in 

 the time unit, about 01 of which was absorbed by 

 the uranium atoms, so it follows that the absorption 

 of 15/10 10 of the emitted 7-impulses by the nuclei of 

 the uranium atoms would have already been sufficient 

 to produce a detectable change in the rate of the 

 disintegration of the uranium. 



(b) Experiments with Radium D. — 1-2 g. radiolead 

 chloride from Joachimsthal of 1 cm. 2 surface was 

 treated in the same way as the uranium oxide for 

 51 days. The /3-activity due to RaE in equilibrium 

 with RaD measured before and after the experiment 

 showed no difference amounting to more than 0-2 

 per cent. Preliminary experiments with X-raj-s have 

 similarly given a negative result. G. Hevesy. 



University, Copenhagen, July n, 1922. 



