December 21, 1911] 



NATURE 



257 



tion in the number of cattle in the country, with a corre- 

 sponding rise in the price of milk and ghi (native butter). 

 It is further urged that the quality of Indian beef is far 

 inferior to that of Australian beef, and likewise that the 

 use of the latter in the Army commissariat would not 

 entail any very great additional cost. 



Mr. a. H. Thayer's suggestive observations upon pro- 

 tective coloration in nature have been described in these 

 columns on more than one occasion, and his son's beauti- 

 fully illustrated work upon it was reviewed in detail a 

 little more than a year ago (October 27, 1910). A number 

 of illustrations from that work are reproduced in colour in 

 the December number of Vearson's Magazine, and the 

 principle they exemplify is described in an instructive article 

 by Mr. Marcus Woodward. Mr. Thayer's view is that it 

 is the rule for animals to be coloured like the background 

 which most concerns their feeding and escape from attack. 

 There are limitations to the application of this interpreta- 

 tion of obliterative colouring throughout the animal 

 kingdom ; but there is no question as to the great import- 

 ance of the principle of countershading in nature, and the 

 article and pictures in Pearson's Magazine should be the 

 means of interesting many people in it. 



The latest issue of The Kew Bulletin (No. 9) is mainly 

 occupied by systematic articles. The most interesting is a 

 description of six new species of Impatiens from Travan- 

 core and Cochin, contributed by the late Sir Joseph Hooker. 

 The list of additions to the wild fauna and flora of the 

 gardens is due in great measure to the collection of speci- 

 mens by members of the garden staff. Noteworthy is 

 the announcement of a heath from Cornwall which appears 

 to be a natural hybrid between Erica tetralix and 

 E. vagans. 



The annual Kew list of seeds of hardy herbaceous plants 

 and of trees and shrubs available for exchange with 

 botanic gardens and regular correspondents has been pub- 

 lished as Appendix I. to The Kew Bulletin (1912). The list 

 reflects in some measure the outcome of the remarkably 

 fine summer, notably in the ripening of the seeds of trees 

 and shrubs ; thus there are offered for exchange the seeds 

 of Clerodendron dichotomum, which has fruited at Kew 

 for the first time on record, Koelreuteria paniculata, 

 liuddlcia globosa, and two species of Halesia. 



Botanical exploration in India is summarised by Major 

 Gage, as director of the botanical survey, in his report 

 for the year 1910-11. An expedition to the south-east 

 corner of Sikkim was undertaken by Mr. W. W. Smith. 

 Captain R. W. Macgregor presented an interesting collec- 

 tion of specimens from the Southern Shan States, and a 

 smaller collection was forwarded by Mr. Burns from 

 Bombay. In the south, the most important contribution 

 was made by Mr. A. Meebold, as the result of an extensive 

 lour through the States of Cochin and Travancore. A 

 -.I'cond fasciculus of the catalogue of non-herbaceous 

 l)hanerogams cultivated in the Calcutta Botanical Gardens 

 lias been published as vol. v., No. 2, of the Records of the 

 i?otanical Survey of India. 



On Monday, December 18, Dr. D. T. Macdougal, 

 director of the department of botanical research of the 

 Carnegie Institution of Washington, lectured before the 

 Royal Geographical Society on the North American deserts. 

 After describing the general characters of desert areas, and 

 explaining the in portance of the various factors involved, 

 he passed on to give a short account of the study of such 

 regions which i^ lp' int; ( arrifd on by the Carnegie Institu- 

 tion. A large series ot lantern-slides, many of them in 



NO. 2199, VOL. 88] 



colour, showed very instructively the character of the 

 desert regions of Arizona and California, and of the types 

 of vegetation which are able to flourish there both under 

 normal conditions and also by the aid of artificial con- 

 structions, such as the concrete walls which are sunk in 

 the detritus-filling valley floors in order to hold up to a 

 higher level the water, which otherwise flows at a depth 

 which is out of the reach of surface vegetation. The 

 formation of the Salton Lake was also described, and its 

 effect on the vegetation of the basin was illustrated. Dr. 

 Macdougal is leaving shortly to visit the deserts of Egypt 

 and the northern Sudan. 



In the Monthly Meteorological Chart of the Indian 

 Ocean for December, issued by authority of the Meteor- 

 ological Committee, a considerable space (as in previous 

 months) is devoted to a useful discussion of ice reports, 

 relating to the southern hemisphere, which subject has for 

 many years occupied the serious attention of the oflfice. 

 In the Southern Ocean icebergs are most frequently met 

 with to the north-east of Cape Horn, south-east of the 

 Cape of Good Hope, midway between Kerguelen and the 

 meridian of Cape Leeuwin, and midway between New 

 Zealand and Cape Horn. Tables of the monthly and 

 annual frequency of the bergs from 1885 to 1910 show that 

 the periods of maxima and minima vary irregularly ; the 

 years of greatest frequency were 1893 and 1906. In the 

 chart for the North Atlantic the ice conditions are also 

 discussed. A sub-chart of the exceptional drifts and heights 

 of bergs shows that the latter were most frequent in the 

 ten-degree square of lat. 4o°-5o° N. and long. 40°-5o° W., 

 but some few were observed nearly so far south as lat. 

 30° N. The first ice seen in 191 1 was on January 28, near 

 lat. 47° N. and long. 52° W. 



In an interesting paper recently published in the 

 Bollettino of the Italian Seismological Society (vol. xv., 

 191 1, pp. 144-53), Prof. G. Grablovitz has traced the varia- 

 tions in the mean level of the sea at Ischia during more 

 than twenty years. From 1890 to 1894 the mean level 

 furnished by the mareograph records remained not far from 

 constant, but from 1895 onwards there has been a marked 

 change, after the effects of barometric variation have been 

 allowed for. The change is not always in one direction : 

 but during the sixteen years from 1895 to 19 10 there has 

 been, on the whole, a rise in the sea-level, the average 

 annual amount being 3 or 4 millimetres a year. The 

 mareograph records at Genoa also indicate a gradual, 

 though much less pronounced, rise in the apparent lev. I o( 

 the sea. 



In his well-known investigations on the after-shocks of 

 earthquakes Prof. Omori finds that the law of decline in 

 frequency is of the form y=:k/(x+h), where y is the daily 

 number of after-shocks at time x after the parent earth- 

 quake, and h and k are constants which vary with every 

 earthquake. Mr. A. Cavasino has recently examined the 

 validity of this formula in regard to the after-shocks of 

 the Riviera earthquake of 1887, one of the first earthquakes 

 in which the after-shocks were studied in detail (Boll. 

 j della Soc. Sismol. Ital., vol. xv., 1911, pp. 129-43). Detcr- 

 I mining the values of the constants from the recorded 

 j numbers of sensible shocks during the first five days, he 

 I shows that the agreement between the numbers furnished 

 i by the formula and of those actually observed is at first 

 i fairly close, but that, after the lapse of 1 f' w years, the 

 ] formula fails to give correct results. Tlic discrepancy may 

 j be due partly, as he suggests, to the difliculty of determin- 

 : ing the average seismicity of the district. It may also be 

 j due to the small number of records used in d. i. 1 mining the 

 I constants of the equation. 



