June 23, 1910] 



NATURE 



499 



ippear, however, that the difficulties are insuperable. Mr. 

 ^arruthers also writes on the cacao canker, caused by a 

 ungus, probably by Spicaria colorans, but possibly also 

 )y others ; Mr. Rorer is working at the problem, and will, 

 t is hoped, be able definitely to allocate the responsibility 

 or the mischief. Mr. Rorer describes the witch-broom 

 Usease of cacao, Mr. Johnston writes on the cocoa-nut 

 »alm diseases, and Mr. Urich on *' froghoppers " in the 

 .ugar-cane (Tomaspis postica. Walk.). Messrs. Carmody 

 ind V'erteuil record certain analyses of local value. 



In a circular published by the L'.S. Department of 

 Vgriculture (No. ii8, Bureau of Entomology) Mr. F. M. 

 A'ebster gives a description of a mite (Pediculoides ventri- 

 •.osiis, Newport) occurring in grain which preys on the 

 arvae of the grain moth, adults of the barley joint-worm, 

 to. It also attacks man, causing an itching skin eruption. 



.\x excellent little " Guide to the Preservation of Health 

 n West Africa," by Dr. Strachan, C.M.G., principal 

 nedical officer of southern Nigeria, has been published by 

 VIessrs. Constable and Co., Ltd., price 6d. net. It deals 

 n simple language with anti-malarial measures, the collec- 

 :ion and storage of water, clothing, food, &-c. 



The Bulletin of the Sleeping Sickness Bureau (vol. ii., 

 '^'" 17, May) contains a very complete scheme of investiga- 

 on the bionomics of the tsetse-fly, Glossina palpalis, 

 rtuiLii conveys sleeping sickness, and should be in the 

 lands of all who desire to do research in this subject. So 

 nuch still remains to be done that probably everyone in 

 Jie endemic areas might, with the aid of a scheme like 

 :his, add his mite to our sum of knowledge. 



The Philippine Journal of Science for December, 1909, 

 ins several papers of considerable medical interest and 

 rtance. Messrs. A. F. Coca and P. K. Oilman record 

 al cases of cancer treated with a " vaccine " prepared 

 inding up a portion of the tumour removed by opera- 

 The results seem promising. Dr. Clegg, by culti- 

 ;:; lepros}- material on agar in symbiosis with amoebae 

 cholera vibrios, claims to have grown an acid-fast 

 --villus which he believes to be the leprosy bacillus. 



1 Pro.=-. Minchin, in his presidential address to the Quekett 



oscopical Club, discusses the phenomena of parasitism 



ig protozoa. He concludes that " in the origin of 



s among parasites tliere are, as in other organisms, 



steps : first, the appearance of variations, with the 



ant disharmony seen in the lethal forms; secondly, 



gradual process of reciprocal adaptation between host 



parasite, the establishment of more normal harmonic 



;ons, associated with definite specific characteristics 



"pactions on the part of the parasite and the host " 



n. Ouekett Microscop. Club, April). 



I A RECENT publication from the Ottawa Government 

 Printing Bureau contains a report by Mr. Einar Linde- 

 tnan to the Canadian Department of Mines on the iron- 

 bre deposits of Vancouver and Texada Islands, British 

 I Columbia. Mr. Lindeman dwells on the importance of 

 jlocal magnetic surveys in the immediate vicinity of the 

 jDutcrops of magnetite, which are a common feature in the 

 district referred to, and gives two interesting charts based 

 J3n such surveys. Unless an appreciable disturbing mag- 

 nnnr force exists for some distance all round an outcrop, 

 Lindeman thinks it is pretty safe to conclude that the 

 — -.nt of the deposit is very limited. 



In the Mimoires de VObservatoire de L'Ebre, No. 4, 

 the Rev. J. Garcia Molld, S.J., describes the equipment 

 of the electric section of the Observatory of the Ebro, 

 NO. 2 12 I, VOL. 8t,] 



founded a few years ago. The work — a French transla- 

 tion from the Spanish — is handsomely illustrated, and 

 extends to more than 120 quarto pages. It describes the 

 apparatus, including a water-dropping electrograph, an 

 Elster and Geitel dissipation apparatus, a Gerdien instru- 

 ment for air conductivity measurements, a ceraunograph, 

 or wireless installation for recording thunderstorms, and an 

 earth-current apparatus. Father Garcia MoUa also discusses 

 in a practical way a number of the difficulties encountered 

 in working the instruments, and goes in considerable detail 

 into the theory of the observations and their reduction. 

 The electrical section is but one of several, and, so far 

 at least as equipment is concerned, the observatory promises 

 to afford remarkable facilities for the study of geophysics. 



In a paper entitled " Storms and Storm-warnings on the 

 German Coast in the Years 1896-1905," published in Aus 

 dem Archiv der Detttschen Seewarte (vol. xxxii., part ii.). 

 Dr. L. Grossmann discusses in great detail the storm 

 frequency for various seasons and districts, and checks 

 the accuracy of the signals hoisted by the Deutsche Seewarte 

 in everv imaginable way. .\n idea of the labour entailed 

 in the investigation may be gathered from the fact that 

 storm statistics have been tabulated from some 10,000 

 monthly registers supplied by the signal stations. The dis- 

 tribution of storms is divided into two principal types, 

 those which spread in a W.-E. direction and those which 

 take place in connection with depressions over north-east 

 Europe and spread to the westward. About 70 per cent, 

 ot the storm phenomena over the North Sea reach the 

 Prussian coast, while only some 47 per cent, of the storm 

 phenomena on the latter coast also occur on the coast of 

 the North Sea. The success obtained in warning of storms 

 from easterly directions is not very satisfactory, especially 

 in the summer months, but the success for those from 

 westerly directions, especially in the winter season, is very 

 considerable. These results agree in the main with those 

 obtained in a similar inquiry for the preceding ten years 

 (Aus dem Archiv, 1898). 



Prof. Carl Barus, in a report published by the 

 Carnegie Institution of Washington (pp. vi-t-83), gives an 

 account of further experiments on " Condensation of 

 Vapour as induced by Nuclei and Ions." The report 

 begins with a chapter on the nuclei left behind on the 

 evaporation of the pure water drops which are produced 

 in moist, dust-free air when a sufficient degree of super- 

 saturation is brought about by sudden expansion. The 

 colour phenomena associated with clouds formed by 

 expansion — a subject to which Prof. Barus has devoted 

 much attention in previous researches — are dealt with 

 in a second chapter. The principal advance here has been 

 in the use of an approximately monochromatic source of 

 light — the mercury green light — in the study of coronas. 

 The rest of the report deals with the application of the 

 corona method of estimating the number of cloud particles 

 to the study of the ions due to radium, and the deter- 

 mination of the ionic charge. On the assumption that 

 only the negative ions are caught in his experiments, he 

 obtains for the charge carried by the ion values agreeing 

 fairly well with those which have been arrived at by 

 other methods. The object of the author's investigation 

 was primarily to test the accuracy of his optical method 

 of determining the number of nuclei. An interesting 

 feature of the experiments is the scale on which they 

 were carried out. Other physicists who have used the 

 condensation method of measuring the ionic charge have 

 worked with expansion apparatus in which the cloud 

 chamber contained only a few c.c. of air ; Barus used a 

 fog chamber containing many litres, the number of ions 



