488 



NA TURE 



[September 29, 1923 



Royal Photographic 



Sept. 



S(iii.> 



' ii .Ulilll.il r\hll>ll U 111 111 I tic Iw ' 



Sucictv w.i^ <i|iin(il 1)11 S.ilur'la., 



.it the ^ci< I \ s Ikhim', y^ Kussell 



remain open imi;! (i.tclxr i-j, and 



:!.| til liiiH al , tliis year, 



(li\ iMi-l iiil.) iiiiii- -111 p -CI 1 lull-., .nni il \MMild have been 

 a ;.;n-.ii iiii|ii(i\ iiiiciil il tills (liNiMon had been main 

 i.iini'l 111 the t xliibition itself, for those interested 

 111 thcst' luattris prefer a clear classification to sym- 

 metrical hanging. TIhic is a total al)seiice of astro- 

 nomical cxhiliits, and the ixlulniioii is the poorer 

 for it. Still, the space avail.iM*-, ulm li is more than 

 heretofore', is urll filled with lmh..! ainl mti resting 

 work. Anv duc who delights in aimnuls ol all sizes, 

 birds, insects, etc., will find a selei tion of work that 

 probably has never been excelled. Of special interest 

 is Mr. 01i\er (.. Tike's demonstration of the lee of 

 kinematography in his enlargement from a lilm 

 showing in eight stages at half second inier\als a 

 cuckoo approaching a meadow pipil s nest, taking 

 out one of the eggs, laying its own egg, and flying off 

 with the stolen egg, which it then eats. 



The American Raylo Corporation illustrate Mr. 

 H. C. J. Deek's three-colour process, which does for 

 colour prints on paper what the introduction of 

 gelatin plates did for ordinary negative making. It 

 simplifies the operations and eliminates many of the 

 difficulties. The three negatives are taken con- 

 secutively, side by side, on a small plate, but the 

 changing of the screens and the shifting of the plate 

 are done mechanically, and the total time occupied 

 may be as short as one quarter of a second. Each 

 record on the triple negative measures i in. x i^ in. 

 Development is done in a metal box, no dark room 

 being necessary. The final prints are 5 in. x 7 in. 

 The negative is enlarged upon a sheet which has 

 upon it side by side the necessary red, yellow, and 

 blue pigmented and sensitised gelatin films, each on 

 a thin sheet of celluloid. It is developed in warm 

 water, and the superposition of the three is done 

 by means of a special adjusting frame, so that the 

 accurate register is very easily secured. 



The radiographic prints exhibited are specially note- 



Society's Exhibition. 



1 he human liand t.ikeii uitli an exposure 

 iiti.tli '>\ .. .-...nd i,v Mr. .\, \. (•....-». 

 >.\Mntoii 1-, I . . ith t he radiograph liia 



( aiiipbell Sv. ; \s^>>, \\\\i- |ir-,t made !!■ 



which recjuired 20 minute^ exposure. 

 Knox shows, among others, radioi^rapi. 

 ih'- movement of tfie left bordi-r of the he 

 normal ( ondition and in ri < .^-^e o( heart block 

 arc tak< • rat^ni and a moving ithn. 



Then ..• section of photomicn 



graphs wlucli mtludcs examples of almost evei 

 possible kind. Mr. I-'. Martin-Duncan has prcpar 

 specimens of the hairs of the prim I 



mounting process and illuminated 1 



manner, so as to show the extremely (leiKat. r 



scales on the outer surface. These are of : 

 portance as a certain means of irlcntificate.; 

 classification. Mr. J. H. Pledi^e sllow■^ a series v, 

 demonstrates tlic variation of stem structure m 

 successive years of a twig of mistletoe. 



Specimens of the use of the Low-Hilcer \n,liorM,'t*.r 

 are shown b\ I't. .• low and also : 

 These include tiie .Mel ha trill, the \\ 

 the cure of corns on the vocal chords, an 

 records of several musical instruments. 



The I\o\al .\ir io- series of photograp:.^ 



taki'ii from aer(.>plani demonstrate to wh.it a 



wonderful degree of perfection ■ thod of work 



has Inen developed. Two aer m collision at 



Northolt last June were photograplicd at the criii 

 moment 1)\- .Mr. (.. V. Grundy. Mr. H. Rous : 

 show^s drawings of the apparatus used for t!,- 

 correction of aerial photographs and the production 

 from them of plan maps, with specimens of the steps 

 in the process. 



Among the stereoscopic prints, lantern slides, 

 and colour transparencies will be found many of 

 excellent quality. The " Cine-Kodak " and the 

 " Kodascope," which reduce the cost of taking 

 " moving pictures " to one-fifth that of the standard 

 apparatus, will be demonstrai \ 30 a.m. and 



3 P.M. each day. These maclr already been 



referred to in these pagt September i, 



P- 333)- 



The European Drought of 1921. 



A LENGTHY discussion of diverse aspects of the 

 ■^^ ".(reat drought is afforded by Prof. Filippo Eredia 

 in a paper entitled " Ea Siccita del iQii," published on 

 the anthorilN' of the .Ministry of Public Works, Koine, 

 in lyi-i. Ailhough the dry weather of tliat year 

 appears to have atiected in varying degrees practic- 

 ally the whole of Europe, and in conjunction with 

 the political situation led to the terrible famine in 

 Russia, the region dealt with in this communication 

 is limited to Italy, Switzerland, France, and Britain, 

 and for the last-named country the author avails him- 

 self of the material supplied by Messrs. Brooks and 

 Glasspoole (Quart. Journ. Roy. Meteor. Soc, vol. 48, 

 1922). 



In Ireland, and in Scotland except on the east 

 coast, the rainfall of 1921 did not, as a rule, fall 

 below 80 per cent, of the normal, and as over much 

 of these two countries the normal amount is heavy, 

 the deficiency of 20 per cent, did not mean any real 

 condition of drought except, perhaps, for quite brief 

 periods now and then during the course of the year. 

 But in eastern and southern England, and the major 

 portion of France, the total fall in 192 1 only amounted 

 to from 60 to 50 per cent, of a much lower average. 



so that the economic consequences of a ueiicie:;> \ 

 equal to half the average were very serious. Local 1\- 

 in the extreme S.E. of England the rainfall of lyii 

 was less tluui 50 per cent, of the average, while in many 

 places in southern and eastern France, Switzerland, 

 and northern Italy it Ixirely exceeded 40 per cent., 

 i.e. a deficiency of nearh- ih , 11, r cent. In London the 

 rainfall of the year was ■ least 150 



years, and was actuaily ie- nation — 



a very rare occurrence in the ilamp, cool climate of 

 England. But whereas in England, France, and 

 Switzerland the most intense phase of the drought 

 coincided with the midsummer heat of June and 

 July, in Italy the dearth of rain did not become acute 

 before September, after which in northern or con- 

 tinental Italy there was practically no rain till the 

 beginning of \^mi, the month of October, normally 

 the wettest in the year, being absolutely rainless at 

 ^lilan and other places — a unique occurrence for that 

 month. 



In central anil southern Italy, on the contrary, the 

 deficiency of rainfall in the last tliree months of 192 1 

 was less marked than in the north, while the normal 

 summer Mediterranean drought of peninsular and 



NO. 2813, VOL. 112] 



