I ! i \rv !(>. tg i'i ' 



NATURE 



3*5 



has come from Spain and \hi.a instead of from the 

 Atlantic, as in the west But as the result of observa- 

 tions of temperature in the upper air I have latterly 

 thought that Mr. II estion is correct, and 



thai the high temperature is due to a descending 

 current. So far as my recollection goes, the pheno- 

 menon occurs- whin an anticyclone is situated over 

 France or the south-east of England, and not in 

 cyclonic conditions such a* have prevailed during the 

 past week. 

 Whatevei th he temperatures and 



- of the air from 2OO0 ft. to 25,000 ft. are 



1 ; from 10,000 ft. to 20,000 ft. the 



correlation coefficients between temperatures and pres- 



the same height are as high as 080 to o-qo, 



11 at -'(ifio ft. the temperature is far more 

 dependent upon the pressure at 30,000 ft. than it is 

 upon the direction of the wind. Above 35,000 ft. the 

 correlation is negative. It seems prettv clear that this 

 close connection between temperature and pressure 

 must be due to vertical currents induced by the dis- 

 tribution of pressure; it is too close, and above 

 30,000 ft. of the wrong sign, to be accounted for by 

 the mere adiabatic compression and expansion with- 

 out change of height, and it may well be that on 

 some occasions the descending currents reach the sur- 

 face and produce a high temperature, although in 

 general the temperature at the surface is not much 

 influenced by the pressure. W. H. Dines. 



Benson, January to. 



Cyclones. 



"J. S. D.," in his interesting article in Nature for 

 January 2 last, makes the following statement : — 

 "Thus the cyclone was looked upon as a warm 

 column of rising air with spirally inflowing winds 

 at its base; the anticyclone, conversely, contained a 

 cold core of descending air. Now we know that the 

 opposite is in reality the truth ; the cyclone has a cold 

 core, the anticyclone a warm one." 1 think it 

 should be pointed out that this pronouncement is only 

 correct for the troposphere, but not for the strato- 

 sphere. 



Modern methods of sounding the atmosphere have 

 shown that the Arctic and Antarctic cyclones have 

 warm centres in the stratosphere, and Dines (Met. 

 Office Pub., 210&, p. 50) shows that this is true of 

 travelling cyclones also. 



Too much importance has been attached to the 

 temperature distribution in the lower portion of the 

 sphere. Modern discoveries have merely located 

 the hot core of the cyclone in the stratosphere instead 

 of in the troposphere, leaving the temperature theory 

 still the cause of the cyclonic circulation of the wind 

 and the force that lifts up a cool central column of 

 air from the ground. 



I think it will be found that the energv of 

 ones can be maintained on the temperature theory 

 with ght interchange of air between the 



stratosphere and troposphere in the case of the polar 

 cyclones, and in the case of travelling cyclones by the 

 bodily rising of the air in the central regions during 

 omparatively brief life. 



R. MoUNTFORD DEELEY. 



25 Bearonsfield Villas, Brighton, January 4. 



Mr. R. M. Deeley is quite right in pointing out 

 that it is only in the troposphere that depressions are 

 relatively cold and anticyclones warm. It is in this 

 n that the striking contrast appears between the 

 old preconceived theory which postulated a warm core 

 and the results of modern observation. The mechanism 

 by which a cyclonic depression is maintained in being 

 NO. 2568, VOL. I02] 



forms one of the great unsolved problems in meteoro- 

 logy. Some years ago the suggestion was out forward 

 i Mr. W. II. Dines that the driving force of the 

 ■ I' [(cession was to be looked for in the level at the 

 of the stratosphere. According to this view, a very 

 slowly descending, and therefore warmed, column o'f 

 air in the stratosphere is just such an integral part of 

 the whole system as the rising, and therefore cold, 

 column in the troposphere, but neither the one nor the 

 other is to be regarded as the cause of the depression. 

 Mr. Deeley may be right in his view that the warm 

 column in the upper layers is the fundamental cause, 

 but this view is not at present generally accepted. 



J. S. D. 



The Brussels Natural History Museum. 

 Ici many of youi readers who appreciate the value 

 of the collections in the Brussels Museum, the fol- 

 lowing extract from a letter written by Dr. Dollo on 

 January 5 will be welcome news : — " Mais je vous 

 avais ecrit egalement ime carte postale illustree, repre- 

 sentant notre Galerie des Vertebras vivants et fossiles 

 de la Belgique, pour vous dire que tout etait bien ici, 

 que noire Mitsee est intact, qu'il n'v manque absolu- 

 ment rien, et que nous etions saufs ! " 



A. C. Seward. 

 Downing College Lodge, Cambridge, 

 January 12. 



BORINGS FOR OIL IN THE UNITED 

 KINGDOM. 



THERE is no need to labour the importance of 

 liquid fuel in our national economy and 

 existence. The growing needs of our Navy and 

 Air Service, and the difficulties of transport 

 during the war, have driven home the lesson and 

 rendered imperative the demand that we should 

 increase to a maximum the output of liquid fuels 

 in the British Isles. The present production, 

 mainly from the Scotch oil-shales and some of 

 the coal-tar distillates, is very inadequate, and 

 the country has had to depend almost entirely on 

 foreign supplies. Such a state of affairs is obvi- 

 ously deplorable, and if remedies are possible the 

 neglect to apply them would be highly culpable. 

 Two methods of alleviating the situation have 

 been suggested, and both are being tried. The 

 first entails the extensive retorting of British oil- 

 shales and cannels to produce oil by destructive 

 distillation; the second involves the drilling of 

 wells in selected areas in a search for free crude 

 petroleum in commercial quantities. With the first 

 method the present writer is not here concerned ; 

 it is the attempt to find oil in the free state which 

 forms the subject of the ensuing remarks. 



The generally received opinion, that Nature, so 

 lavish in her gifts of coal and iron to these 

 favoured islands, was unaccountably frugal with 

 petroleum, has not been accepted by all. A small 

 minority has urged, and recently with insistence, 

 that the assumption is based largely on the 

 absence of definite intelligent exploratory drilling — 

 that we are, in fact, in the same position as the 

 United States before the Drake well of 1S59, 

 ignorant of the great stores of wealth lying avail- 

 able below the surface. 



If this view be sound its importance cannot be 



