516 



NATURE 



[January 7, 19 15 



cultivation, and distribution of improved varieties of 

 tropical fruit plants have been actively carried on at 

 two experimental stations, while similar attention is 

 being given to temperate and subtropical fruits at a 

 third station. Detailed notes are given regarding a 

 considerable number of fruits and vegetables which 

 have been found to thrive well in different parts of the 

 Protectorate. 



The remarkable character of the South African flora 

 is emphasised by Dr. R. Marloth in his recently 

 delivered presidential address before the South African 

 Association for the Advancement of Science, at the 

 meeting held at Kimberley. It is also of interest to 

 note that Dr. Marloth was this year the recipient of 

 the South Africa medal and grant for research, 

 founded by members of the British Association in 

 commemoration of their visit to South Africa in 1905. 

 The adaptation of the vegetative organs of plants to 

 their environment occupies part of the address, and 

 some of the most striking examples are furnished by 

 several species of Mesembryanthemum, Anacampseros, 

 and Crassula. M. bolusii and M. simulans exactly 

 resemble the singular stones among which they grow, 

 both in shape, colour, and texture. The examples 

 grown at Kew show how stone-like these and other 

 species may be even when grown under glass. The 

 papery-white Anacampseros papyracea, which grows 

 among white quartz, is one of the most difficult of 

 plants to detect in its native habitats. Mesemhry- 

 anthemum calcareum, which grows in a lime-tufa 

 region, has the surface of the leaves roughened, 

 exactly resembling the limestone among which it 

 occurs. The colours of some species of Mesembry- 

 anthemum and Crassula are also found to vary in 

 accordance with the type and colour of the soil on 

 which they are growing. Examples of this curious 

 mimicry or adaptation in the South African flora 

 might be multiplied, but the explanation of the pheno- 

 mena is not easy to suggest, and experiment is needed 

 to prove whether, as Dr. Marloth suggests, the light 

 reflected from the soil may be capable of producing 

 a reaction in the plant. 



Illustrations of the importance of magnetometric 

 surveys in tracing iron ores are given by Mr. E. 

 Lindeman in papers on the magnetite of Calbogie, 

 Ontario, and on the famous Moose Mountain district, 

 near Sellwood, in the same province (Canada Depart- 

 ment of Mines, Mines Branch, 1914). Several de- 

 tailed maps accompany the latter paper. The geo- 

 logical relations of the iron-bearing rocks at Moose 

 Mountain have been described by Prof. Coleman for 

 the Ontario Bureau of Mines (" Excursion to the Sud- 

 bury Area," Guide Book No. 7, 1913) ; but much 

 remains to be done in distinguishing between the 

 material of igneous origin and the rocks into which 

 both granite and diorite have intruded. The possi- 

 bility of a sedimentary origin for the Moose Mountain 

 series is by no means excluded, in view of the similar 

 bedded siliceous iron o' es of South Africa ; and the 

 same may be said of the magnetite of Kiruna, which 

 is commonly cited for comparison. The smoothly 

 glaciated surfaces at Sellwood offer excellent oppor- 

 tunities for study. 



NO. 2358, VOL. 94] 



To the State librarian of Hartford, Connecticut, wc 

 are indebted for a copy of the fourth volume of thc 

 Bulletins of the State Geological and Natural History 

 Survey. It is an exceedingly bulky volume, contain- 

 ing half a dozen separately paged bulletins (Nos. ib 

 to 21), originally published at various dates from 1910 

 to 1913, four relating to local faunas, and two to thj 

 work of the survey. The faunistic papers include ( 1 ) 

 the first and second parts of a guide to the insects o; 

 Connecticut, by Messrs. W. E. Britton and B. H. 

 Walden, originally published in 191 1; (2) an account 

 of the Triassic fishes of Connecticut, prepared, with a 

 section on the study of fossil fishes in general, by 

 Prof. C. R. Eastman, also originally issued in 191 1; 

 (3) a survey of the echinoderms of the Connecticut 

 coast, by Dr. W. R. Coe, originally published in 

 1912; and (4) a systematic list of .Connecticut birds, 

 with notes on their habits and distribution, by Messrs. 

 J. H. Sale, L. B. Bishop, and W. P. Bliss, fir:,t 

 issued last year. The first three of these publications 

 are fully illustrated. 



As the time is now approaching when icebergs and 

 other forms of drifting ice will make their appearance 

 in the North Atlantic, it may be of interest to extract 

 a few of the main facts with reference to the behaviour 

 of the ice in 19 14 from the Monthly Meteorological 

 Chart of that ocean for January, 19 15, issued by 

 authority of the Meteorological Committee. Icebergs 

 were seen at Belle Isle early in January, and several in 

 46° N., between 46° and 49° W., with some field ice 

 between January 17 and February 5. On June 17 a 

 berg was passed near 515° N. and 41° W., and on 

 July II another was seen about 46^° N., 402° W. ; 

 these were the easternmost bergs seen up to date of 

 chart (about the middle of December). The loftiest 

 berg of the season was passed near 42° N., 485° W., 

 on May 19 (estimated at 500 ft. high). On July 27, 

 near 41° N., 675° W., a small berg was passed; the 

 furthest west in that year. In a very useful article 

 on the subject by Commander Hepworth, C.B. (marine 

 superintendent) in the "Seaman's Handbook of 

 Meteorology," issued by the committee, he shows that 

 icebergs and field ice reach the trade routes earlier 

 in some years than in others ; the maximum quantity 

 may be met with as early as April and as late as 

 August. Drifting ice may, it is stated, be observed 

 in almost any part of the North Atlantic north of 

 30° N. latitude, about as far east of the loth meridian 

 of v^est longitude on the eastern side of the ocean, 

 and about as far west as the 75th meridian on the 

 western side, north of 35° N. 



In two papers which appeared in the Bulletin of the 

 Bureau of Standards in 1908 and 1912 Mr. W. VV. 

 Coblentz described and compared the sensitiveness of 

 the various forms of radiomicrometers. As a result 

 of a series of measurements he concluded that a 

 thermopile with silver and bismuth as its elements 

 gave promise, when used in vacuo, of a degree of sensi- 

 tiveness about half that of a bolometer under the 

 same conditions, while its readings were much 

 steadier. In a further paper reprinted from the bulle- 

 tin for 1914, he gives details of the methods of con- 

 struction he has found most suitable for thermopiles 



