May 29, 1913] 



NATURE 



V-l 



been dealt with. Heft 55, by Prof. Engler, begins the 

 account of' the Philodendroideae section of the large 

 family Araceae by Engler and Krause, and is un- 

 usually well and fully illustrated with new figures. 

 Heft 56, by Dr. F. Kranzlin, forms a self-contained 

 monograph of the "Indian shot" family, Cannaceae, 

 and concludes the treatment of the interesting order 

 Scitaminales, the remaining three families of which 

 (Musaceae, Zingiberaceae, Marantacese) have already 

 been described by Schumann ; in his introduction the 

 author gives an account of the various interpretations 

 which have been put forward of the structure of the 

 outer floral organs in Canna, the sole genus in the 

 family. In Heft 57, Dr. Pax, assisted by Kathe 

 Hoffmann, continues the monograph of the large and 

 difficult family Euphorbiaceae ; in addition to figures 

 of many of the species, there is given a useful table 

 showing the geographical distribution of the genera 

 belonging to the section (Chrozophorinae) dealt with 

 in this part. Heft 58, by G. Gruning, gives the 

 Stenolobeas section of the same family. 



We have received a copy of vol.. xlviii., No. 8, of 

 the Proceedings of the American Academy of Arts and 

 Sciences, consisting of an extensive memoir by Mr. 

 J. W. Hotson on culture studies of fungi producing 

 bulbils and similar propagative bodies. In this paper 

 the author brings together the scattered references in 

 mycological literature to the occurrence in various 

 fungi of these propagative bodies, which are cell- 

 masses ranging -from spore-like structures to large 

 sclerotium-like forms, and indeed shading gradually 

 into these two definite and distinct types (spore and 

 sclerotium) of reproductive body. After describing in 

 detail, with numerous excellent figures on twelve 

 plates, the structure and development of bulbils in the 

 various species examined during his long-continued 

 culture experiments, the author discusses the morpho- 

 logical significance, distribution, and occurrence of 

 bulbils in fungi. He concludes that in most cases, if 

 not in all, these bodies are not to be regarded as 

 abortive spore-fruits (ascocarps), but rather as an 

 auxiliary method of reproduction that has been inter- 

 polated in the life-history of certain fungi without 

 definite relation to other methods of reproduction they 

 may possess, or that if they have in reality been 

 derived from some other reproductive body, this was 

 more probably some form of non-sexual spore rather 

 than the primordium of an ascocarp. 



The Memoirs of the Indian Meteorological Depart- 

 ment, vol. xxi., part 7, contain an interesting inquiry 

 into the cold weather storms of northern India by 

 Dr. G. T. Walker and Rai Bahadur Hem Raj. It 

 is pointed out that the storms in question, which 

 occur between December and April, are of consider- 

 able agricultural importancej and that it is extremely 

 desirable that their origin should be ascertained, the 

 view that these rain-bearing disturbances are gene- 

 rated over the arid districts of Persia and Baluchistan 

 being by no means free from difficulty. An examina- 

 tion of charts recently prepared by the Meteorological 

 Service of Egypt for the years 1906-12 shows that 

 about seven-tenths of the disturbances which affect 

 north-west India in those months are continuations 

 of depressions from southern Europe, but the paths of 

 NO. 2274, VOL. gi] 



the depressions vary considerably from year to year. 

 In order to confirm the origin of most of the storms 

 without a large expenditure of labour in preparing 

 charts, Dr. Walker had recourse to statistical methods. 

 He says that if these storms pass over Syria or Asia 

 Minor it is to be expected that severe winters with 

 much precipitation in these areas will tend also to be 

 severe winters in north-west India. "A calculation 

 was accordingly made of the correlation coefficients of 

 the seasonal rainfall in north-west India with those of 

 rainfall in places to the west for which records were 

 available." The evidence shows that the winter 

 seasons in the west of Asia Minor, in Syria, and in 

 Malta have a closer resemblance to those of north- 

 west India than do the winter seasons of Persia and 

 Mesopotamia. 



In his presidential address to the Institution of 

 Mining and Metallurgy, delivered on March 13, 

 a copy of which has just reached us, Mr. Bedford 

 McNeill devoted his attention more particularly to the 

 statistics of production of the more important metals, 

 laying especial stress upon the precious metals. He 

 showed that the production of metals was increasing 

 at a rate quite unexampled in the history of the world, 

 the percentages of increase during the decade ending 

 in 191 1 ranging from 29 in the case of lead up to no 

 less than 513 for aluminium, whilst it was 58 for iron 

 and 68 for copper. The metal miner is therefore 

 supplying the world with the metals used in the arts 

 upon an enormously greater scale than ever before. 

 As regards the precious metals, it is shown that 

 within the above-named decade the production of gold 

 has increased by 79 per cent., and that the world's 

 annual output of gold is now more than equal to the 

 total production for the sixty years preceding the year 

 1700. Mr. McNeill shows that this increase of pro- 

 duction is to some small extent counteracted by the 

 remarkable absorption of gold that has been taking 

 place for some years past in India, and to a smaller 

 extent also in Egypt. The production of silver has 

 also undergone an increase, though less than gold, the 

 increase during the decade 1901-11 being 41 percent.; 

 the actual production of silver during that period was 

 ten times as great as that of gold, though this pro- 

 portion is one that appears to fluctuate considerablv 

 from time to time. 



When our knowledge of the mean depth of the 

 oceans was less extensive than it is now, it was 

 supposed that a close approximation along certain' 

 lines was given by the velocity of seismic sea-waves. 

 The formula (Lagrange's) used for the purpose was 

 v=\/(gh), where v is the mean velocity of the waves 

 and h the mean depth along the line of ocean 

 traversed by them. It was shown, however, by Dr. 

 Davison (Phil. Mag., vol. xliii., 1897, pp. 33-36) that, 

 when the depth is variable, the formula gives too 



great a depth, and that it should be v = s I / j - , 1 



being the distance from the epicentre. Prof. Rudski 

 ("Physik der Erde," 1911, p. 340) suggested the 



formula v---\ J(gh)ds. Prof. G. Platania has recently 



made a comparison of the results given by the three 



