158 



NATURE 



[August 4, 1910 



the same methodLj of soil analysis. This would not matter 

 much if the methods were all absolute ; unfortunately, they 

 are mainly conventional. Thus an English analyst will 

 sav that a soil contains 02 per cent, of total potash, mean- 

 ing by this the amount extracted by hydrochloric acid 

 under particular conditions, although the mal total is 

 probably three or four times this amount. Continental and 

 American analysts, working on the same soil, but using 

 different methods, would reach wholly different results. 

 The trouble is still worse in the mechanical analysis of 

 soils. " Clay " in Great Britain means material less than 

 0-002 mm. in diameter, in the United States it stands for 

 particles less than 0-005 mm. in diameter ; elsewhere a 

 widely different limit — o-oi mm. — is adopted; so with the 

 other terms. In consequence, one can never compare 

 mechanical analyses made in one country with those made 

 in another ; the same terms are used, but they denote 

 different things. The confusion thus introduced into an 

 already difficult subject is most unfortunate. One great 

 advantage of international conferences of this sort would 

 be to prevent such confusion arising in the future. 



E. J. Russell. 



SCIENCE '.V SOUTH AFRICA.' 



T^HE Royal Society of South .■\frica consisted at the 

 time of its annual report (.April, 1909) of forty fellows 

 and 160 members ; it had held six meetings during the 

 preceding year, ten papers altogether being read. Part i. 

 of the Transactions, in which these papers appear, con- 

 tains 334 pages ; part ii. contains the papers read at sub- 

 sequent meetings, and has expanded to 477 pages, since 

 there were nineteen papers in place of ten. Most of the 

 papers deal with local matters ; only about half a dozen 

 are concerned with general problems, and of these three 

 are mathematical. 



The local papers are mainly botanical. Dr. Schonland, 

 of the Albany Museum, Grahamstown, gives a full 

 description of Haworthia truncata, Schonl., the only 

 species of Haworthia with strictly distichous arrangement 

 of leaves. The leaves are to a large extent underground, 

 while the exposed parts resemble small pebbles, so that 

 the plant may be classed among the so-called " mimicry 

 plants." Its structure is well adapted to its peculiar 

 mode of life. The truncate apex is w'ithout chlorophyll, 

 and thus fortns a " window " through which light can 

 pass by way of the central transparent tissue to the 

 assimilating tissue which extends to the underground basal 

 parts of the leaves. Dr. Marloth describes other plants 

 possessing the same structure. 



Experiments were also made to find out whether the 

 aerial parts of plants, particularly those growing in arid 

 regions, can absorb moisture from the air. In the Karroo 

 there is commonly a fall of dew at night. Dr. Marloth's 

 experiments indicate that the native plants can take 

 sufficient moisture from this source through their leaves 

 to satisfy their requirements. Dr. Schonland, on the other 

 hand, is not satisfied on this point ; the plants examined 

 by him did not appear to absorb from the air anything 

 like a sufficient quantity. 



Mr. A. L. du Toil, of the Geological Survey, describes 

 the evolution of the river system of Griqualand West. 

 This system is very complex, but its history can be traced 

 to a remote geological period. In Palaeozoic times a 

 continent, at a level lower than the present, extended over 

 this area, the drainage from it being directed southwards 

 mainly along the Kaap valley. .At the close of the 

 Carboniferous epoch this continent was intensely glaciated, 

 and finally buried beneath the Permo-Triassic Karroo 

 deposits; upon the surface thus formed the modern drain- 

 age system was initiated. In later periods — in late 

 Jurassic, Cretaceous, and Tertiary times — there has been a 

 succession of uplifts, but the rivers have been enabled to 

 cut a peneplain. One of the most important of these 

 surfaces extended from the Stormberg probably into 

 Griqualand West, where it is represented by the Kaap 

 Plateau. This surface has suffered denudation, and the 



1 Transactions of the Royal Society of Poiuh .Africa, vo'. i., 1910. 

 The South African Journal of .Science, vol. vi., 1909-10. 



NO. 2127, VOL. 84] 



rivers have cut down and laid bare the pre-Karroo floor 

 with its drainage lines. 



Dr. Broom discusses the relationship of the South 

 .African fossil reptiles to those found in other parts of the 

 world. The Lower Karroo fauna of South Africa shows 

 many points of reseinblance to the Permian in America ; 

 it seems practically certain that both are modifications of 

 an earlier fauna which probably inhabited a southern 

 continent joining Brazil and South Africa. The .American 

 types are considered to be nearer the ancestral, though 

 considerably specialised ; the .African, probably owing to 

 their living in the swamps of the Karroo, developed greater 

 length of limb and tended to become more active ; but 

 in South Africa the conditions must have been such as to 

 promote rapid evolution, for many new types soon 

 appeared, the most remarkable being the Anomodonts, 

 which probably originated there. Towards the end of 

 Permian times a land connection with Europe seems to 

 have formed, by which the pareiasaurian fauna passed 

 into Europe ; still later — in the Upper Triassic beds of 

 Burghersdorp — a nuinber of European types passed into 

 -Africa without, however, any of the Cynodonts, highly 

 characteristic of this period in .Africa, passing back in 

 return. In Lower Jurassic times land connection was well 

 established. There is evidence of continuous land between 

 Africa and .Australia in Upper Triassic times. 



The mathematical papers by Dr. Muir deal with a 

 theorem regarding a sum of differential coefficients of 

 principal minors of a Jacobian, an upper limit for the 

 value of a determinant, and Borchardt's form of the 

 eliminant of two equations of the nth degree. Other 

 papers deal with the spectrum of the ruby, snake venom, 

 the rainfall of South Africa, evaporation in a current of 

 air, a list of the flora of Natal, and so on. 



The South African Journal of Science is the organ of 

 the South African Association for the Advancement of 

 .Science, its objects being to give a stronger impulse and 

 a more systematic direction to scientific inquiry, to obtain 

 a more general attention to the objects of pure and applied 

 science, and the removal of any hindrances barring the 

 progress of science. Instead of issuing one large annual 

 volume, like our own association, a small journal is sent 

 each month to the inembers. The numbers of the present 

 volume (vol. vi., beginning November, 1909) contain the 

 presidential addresses and some of the papers read before 

 the sections ; notes and articles from other sources are, 

 however, included. The papers, nearly sixty in all, have 

 the general merit of dealing with local phenomena, thus 

 putting on record something that may pass away and be 

 lost, or else attacking problems that can only be investi- 

 gated on the spot. 



It is eminently satisfactory to find that sufficient material 

 exists to keep going these and the other scientific journals 

 and societies of South Africa, including the geological, 

 the chemical, and the engineering societies. South 

 Africa has hitherto loomed so largely in the political and 

 commercial worlds that it will come as a surprise to 

 some to find that research work has been going on quietly 

 and steadilv for several years. The foundation has been 

 laid on which a great superstructure may be raised ; it 

 has been proved that the fauna and the flora show in 

 relation to their surroundings many features of very general 

 interest and importance ; a number of problems have thus 

 been suggested for future workers to attack. Most 

 important of all, however, is the fact that the spirit of 

 research is abroad in South Africa at a time when colleges 

 and universities are being founded and agricultural depart- 

 ments developed. There is, in consequence, the prospect 

 that these new foundations may be started in the right 

 direction at the outset, and so attain a position worthy 

 of the vast possibilities of the country. The men who are 

 now devoting themselves to research work are therefore 

 making more than an examination of local problems, 

 important as this is in a developing country where develop- 

 ment often means extermination of species and obliteration 

 of old records. They are creating an atmosphere in which 

 the college and departmental staffs can do research work, 

 in which, indeed, men will feel impelled to investigate. 

 To do this in a busy commercial country like South .Africa 

 is no small achievement. 



