July ii, 1918] 



NATURE 



73 



journal, which contain much valuable information in 

 regard to the avifauna of South Africa ; the Transvaal 

 Biological Society, which was founded in 1907, has 

 held a number of meetings in Pretoria, to which many 

 papers and demonstrations have been submitted, but 

 it has not issued any publication of its own. The 

 new journal,, which is edited by Messrs. A. K. 

 Haagner, I. B. Pole Evans, and Claude Fuller, con- 

 tains a number of useful papers, chiefly on ornitho- 

 logical and entomological subjects. Lieut. G. C. Finch- 

 Davies writes on the birds of the districts of Okan- 

 jande and Outjo, in the South-West African Protec- 

 torate, formerly German South-West Africa, a region 

 much neglected since the days of C. J. Andersson and 

 F. Eriksson, who collected in the sixties and seventies 

 of the last century. Other bird papers are contributed 

 by Messrs. C. F. M. Swynnerton and R. Godfrey. 

 Mr. Haagner describes a new baboon (Choiropithecus 

 rhodesiae) based on an animal living in the Zoo- 

 logical Gardens at Pretoria, and illustrated by a photo- 

 graph — a rather hazardous proceeding, perhaps, while 

 the animal is still alive. Among the entomological 

 papers are one bv Mr. R. W. Jack on the larvae of 

 some Rhodesian Tonebiionidse, and one by Mr. C. N. 

 Barker, in which attempts are made to explain some 

 irregularities in the phenomenon of seasonal cfimorphism 

 among butterflies. Altogether the part, which consists 

 of 122 pages of well-printed text, is a welcome addition 

 to the list of zoological publications, and, we hope, will 

 continue to appear and to maintain the high standard 

 it has set itself. 



In view of the increasing restrictions upon the im- 

 portation of wheat, the Department of Agriculture for 

 Trinidad and Tobago has issued a leaflet entitled " Our 

 Local Foods and How to Use Them," which urges 

 economy in the use of wheat-flour and the more ex- 

 tensive use of native plants — sweet potatoes, yams, 

 cassavas, dasheens, and others — as human food. The 

 leaflet embodies many of the recommendations of the 

 British Guiana Flour Substitutes Committee, which 

 was appointed in 19 17 to investigate the possibility of 

 procuring locally grown products as substitutes for 

 wheat-flour. The report of this Committee, which 

 was published in the Bulletin of the Department of 

 Agriculture for Tfinidad and Tobago {vol. xvi., part 2), 

 states that the products of tropical origin which most 

 nearly approach wheat-flour in food value are rice, 

 guinea-corn, and maize, but it is not possible to make 

 bread of these alone; they can be employed only in 

 the preparation of cakes. On the other hand, these 

 products, and, in addition, cassavas, sweet potatoes, 

 and tannias, are useful adjuncts to imported flour, 

 and by their general use in bread-making it was cal- 

 culated that the amount of wheat-flour imported in 

 1916-17 might be reduced to half in 1918. The 

 economical feeding of stock is also strongly urged bv 

 the Department of Agriculture, as in 1914 oats and 

 cattle-food to the value of 70,000?. were imported. As 

 a substitute for oats, farmers are recommended to 

 grind unshelled corn and to supplement it with locally 

 grown peas and beans, as this practice should reduce 

 the imported cattle-fodder to about one-fifth of its 

 present amount. The high price of food has largely 

 increased the area of land under cultivation in Trinidad, 

 and the Government has recently offered rice lands at 

 .1 nominal rental, so that the colony should become in 

 the future largely self-supporting. 



A SEVERE earthquake, of which very few details 

 have as vet reached this countn.-, occurred at about 

 6 a.m. (G.M.T.) on February 13 in Swatow, on the 

 southern coast of China, by which several hundred 

 persons were killed and more than a thousand injured. 

 An account of the earthquake, written for the most 

 NO. 2541, VOL. lOl] 



part in Japanese, is given by Mr. K. Hasegawa in a 

 recent issue (March, 1918) of the Journal of the 

 Meteorological Society of Japan. The position of the. 

 epicentre, as determined from records obtained in 

 Japanese observatories, is in lat. 24° N., long. 116° E, 



That the duration, of the preliminary tremor of an 

 earthquake varies with the distance of- the epicentre 

 has long been known, though, for earthquakes with 

 neighbouring origins, no simple formula has been 

 devised for estimating the distance of the epicentre 

 from the duration of the tremor. From a discussion 

 of forty-one recent earthquakes in Japan, Prof. Omori 

 shows (Bulletin of the Imperial Earthquake Investiga- 

 tion Committee, vol. ix., 1918, pp. 33-39), that, when 

 the distance does not greatly exceed 1000 kilometres, 

 the distance of the epicentre in kilometres is very 

 nearly 742 times the number of seconds in the dura- 

 tion of the preliminary tremor. The only exception 

 within the limit mentioned is that if the duration is. 

 less than one second the coefficient should be 6-o. 



Mr. J. B. Tyrrell (Trans. Roy. Soc. Canada, voL 

 xi., p. 39, 1917) concludes that' the deep vegetable 

 deposits known as "muck," resting on permanently 

 frozen gravels in the Klondike district, began ta 

 accumulate at the very opening of the Glacial epoch. 

 The supply of gravel through river action was then 

 cut ofi", and conditions were established which have 

 lasted down to the present day. The permanently 

 frozen substratum furnished an impervious founda- 

 tion, on which sufficient water gathered in spring to 

 allow of the growth of Sphagnum and Hypnum, while 

 the streams from the hill-slopes washed down into the 

 flats representatives of the forest flora of the district. 



Mr. p. W. Stuart-Monteath {Comptes rendus^ 

 January 7, 1918) gives reasons for assigning a 

 Cretaceous age to a large extent of limestone, once 

 regarded as Carboniferous, in the *' Detroit de la 

 Navarre," a transverse band of sediments separating 

 the Pyrenees from the Basque ranges. He concludes 

 that a great series of intrusive ophites and Iherzolites 

 is responsible for the local silicification of various- 

 rocks, and that the intrusions are posterior to the 

 Hippurite-limestone and to an overlying conglomerate. 

 The conglomerate contains blocks of ophite, which are 

 interestingly regarded as due to volcanic explosions 

 prior to the veins that were finally injected in the 

 mass from the same subterranean cauldron. 



Although a number of weakly magnetic minerals 

 such as zinc-blende are known to be attracted by 

 strong magnetic fields, but little is known as to the 

 degree of magnetisation obtainable. Three investiga- 

 tors describe in Metall und Erz for January 8 a method 

 of measuring the susceptibility of such minerals- 

 Zinc-blendes of difl'erent varieties were found to have 

 widely varying susceptibilities, some being below 

 10-* and some as high as 500 x 10-*. 



In the Revue ginirale de I'Electricile for May 18 

 methods are described to enable electric generating 

 stations to transmit signals over their systems. These 

 signals could be used for such purposes as time- 

 signals, synchronising clocks, or giving any other pre- 

 arranged signal, such as air-raid warnings, etc. The 

 signals consist of a series of periodic variations of 

 voltage, the magnitude being small compared with the 

 line voltage. 



At the present time, when oils and grease are of 

 so much importance economically and industrially, a 

 writer in La Nature for April 27 describes a new 

 process, invented by an Italian (Prof. Lotrionte), that 

 has proved most successful in exterminating the olive- 



