412 



NATURE 



[July 25, 191: 



a dynamic study of the facts relating to survival keeps 

 in touch with reality as manifested in the life-force. 



In the South African Journal of Science (vol. xiv., 

 No. 4) for November, 19 17, Prof. J. W. Bews discusses 

 the plant-succession in the thorn veld. The acacias, 

 especially Acacia horrida and A. arabica, are the 

 pioneers', as they are able to establish themselves with 

 no shade, shelter, or protection against grass-fires. 

 After they are established many other species, ger- 

 minating in the seed-bed prepared for them by the 

 activity of earthworms, termites, and ants beneath the 

 thorn-tree, grow up in the shade. Various stages have 

 been traced, and ultimately the subsequent species 

 mav kill the pioneer. As a" rule, however, the thorn- 

 trees remain dominant in what is, at present, over 

 the largest areas, the final stage. Seed-dispersal is 

 little due to wind, the- chief agents being birds, but 

 for species with capsular fruits and small seeds, ants, 

 which are very abundant, play an important part. 

 Termites also exert important influence on the plant- 

 succession. 



The various forms of " scab " found on potato-tubers 

 have for long been more or less puzzling to plant 

 pathologists. The investigations of recent years have 

 considerably enlarged our knowledge of parasitic 

 organisms such as Synchyirium endobioticum, Spongo- 

 spora stibterranea, Act'nomyces chr onto genus , etc. , and 

 of their effects upon the tuber. Workers in this 

 domain of research will be interested, therefore, in a 

 paper published in the Journal of Agricultural Re- 

 search for May 27 by Mr. J. J. Taubenhaus, who 

 describes a form of scab of the sweet potato which he 

 calls "Pox," and which also occurs on the ordinary 

 potato (Solanum tuberosum). According to this 

 author, the causative parasite in this case is a 

 myxomycete named Cystospora batata, Ell., which 

 probably hibernates as cysts in the soil. It would be 

 interesting to know whether this organism occurs in 

 the Old World as well as in the New, and doubtless 

 the publication of the paper referred to will stimulate 

 search for it. 



The damage to tomatoes and other valuable glass- 

 house crops due to the root-nematode or eelworm 

 {Heterodera radicicola) is widespread and consider- 

 able, and, so far, no economical and effective measures 

 of control have been devised. Some experimental work 

 on this subject is described in an article by Mr. 

 Willis P. Durz in Soil Science (vol. iv., No. 6), in 

 which the application of sodium cyanide to infested 

 greenhouse soil was tested, and under certain condi- 

 tions gave satisfactory results. The cyanide dissolved 

 in water was applied in the proportion of 200 lb. per 

 acre, one-third gallon per square foot of soil, as weaker 

 solutions were found to be ineffectual ; one week after 

 the first treatment a second similar treatment was 

 given. In order to bring out the larvae from their 

 cysts the soil was kept moist and warm for about 

 five days before each application. All plants should be 

 removed from the soil before applications of sodium 

 cyanide at this rate, and the soil should be aerated 

 and leached to remove any traces of cyanide gas before 

 replanting. Other methods of control recommended 

 are the application to the soil of formaldehyde and of 

 sphagnum-moss extract and the raising of the tem- 

 perature of greenhouses to 101° F. 



The latest addition to Messrs. E. Stanford's series 

 of war-maps is a map of Denmark, Schleswig-Holstein, 

 etc., published at the price of half a crown. The 

 scale is approximately i : 1,140,000. No relief is 

 shown, but water under ten fathoms is coloured lighter 

 blue than water of greater depth. International 



NO. 2543, VOL.' lOl] 



boundaries on land are shown in red. It would have 

 been useful to mark the boundary of the Danish Archi- 

 pelago towards Sweden and Germany by a dotted line. 

 The map has plenty of names, and railways are clearly 

 marked. The courses of the British and German fleets 

 at the Battle of Jutland are shown in red. 



We have received from the Commonwealth Meteoro- 

 logist a copy of the rain-map of Australia for 1917. 

 Besides the chief map showing the details of the 

 annual rainfall, the sheet has smaller maps giving the 

 rainfall for each month during the year. The small 

 maps are clear, but the principal one is very obscure 

 in places. Previous editions had not this defect, and it 

 is to be hoped that it represents merely a passing phase 

 of difficulty in printing. The abnormal conditions of 

 rainfall were even more pronounced in 19 17 than in 

 19 1 6, and 75 per cent, of the area of the country had 

 a rainfall above the average. Some parts of Western 

 Australia had the wettest year on record. Throughout 

 the wheat belt rains in general were much above the 

 normal, especially during August, September, and 

 October. In parts of Victoria, New South Wales, and 

 Western Australia too much rain injured the wheat 

 harvest, the returns of \vhich were considerably below 

 the average. The unusual conditions are attributed by 

 Mr. H. A. Hunt partly to the strong monsoonal in- 

 fluences in summer and partly to the exceptional 

 development of southern low pressure in winter. Very 

 similar conditions prevailed in 1916. 



In the Journal of the Royal Society of Arts 

 (No. 3417, May 17) Mr. Alfred Dickinson discusses 

 "Water-power in India." As an example he quotes 

 the dam across a valley in the Western Ghats con- 

 structed by Messrs. Tata, Sons, and Co., which pro- 

 vides 300,000 h.p. continuously. Mr. Dickinson is 

 now investigating the possibility of utilising the irriga- 

 tion lake at Perigar, in the Madras Presidency, for 

 power purposes, and numerous other schemes of the 

 same kind are possible. With its enormous supply 

 of minerals for metallurgical development, materials 

 like cotton, flax, and jute, and abundant and cheap 

 labour, a great commercial and industrial development 

 may be expected. "Although much has been done, 

 her industrial possibilities, to use a vulgarism, have 

 scarcely been ' scratched. ' " 



The Engineering Experiment Station of the Uni- 

 versity of Illinois has published Circular No. 6, March, 

 1918, by Prof. H. H. Stock, upon the storage of 

 bituminous coal. This subject has attracted con- 

 siderable attention within the last few months on 

 both sides of the Atlantic, papers having appeared on 

 the subject in the publications of the Canadian Depart- 

 ment of Mines and in the Transactions of two English 

 engineering societies, whilst the theory of the spon- 

 taneous combustion of coal, which forms, or should 

 form, the basis upon which all methods of coal storage 

 are based, has been worked out at the Doncaster 

 Coalowners' Laboratory. The present circular prac- 

 ticallv disregards the theoretical side of the subject, 

 but concerns itself more particularly with the en- 

 gineering features of coal storage. The various 

 methods of storing coal are described in much detail, 

 and, amongst others, the method of storing _ under 

 water is fullv considered. The various precautions in 

 the way of thorough ventilation of the pile, restricting 

 its height and subdividing it suitably, as well as the 

 proper grading of coal intended to be stored, are all 

 discussed, and stress is laid upon the importance of 

 regular inspection and determination of the tempera- 

 ture of the pile; the author holds that when the tem- 

 perature reaches 150° F. the pile needs to be care- 

 fully watched, and if it rises to 175° or 180° F. the 

 'coal should be removed as promptly as possible. 



