38o 



NATURE 



[August i; 



Some of these features are characteristic of desert-plants. 

 Many desert-plants have reduced transpiring surfaces and hidden 

 stomates. They often have very long roots, as was particularly 

 observed in the excavations for the Suez canal. ^ The leaves are 

 often small and crowded, the stems woody, much branched and 

 tufted. Bright sunlight retards growth, and green tissues hardly 

 ever present a large absorbing surface when they are habitually 

 exposed to bright light. Accordingly the young shoots and 

 branches do not push out freely, but try to hide one behind 

 another. The tissues of desert-plants may be remarkably dry ; 

 they are often, however, remarkably succulent ; the plant either 

 learns to do without water for a long time together, or to store 

 it up. 



It is not without surprise that we learn how similar are the effects 

 of tropical drought and of Arctic cold. The facts of distribution 

 would in themselves suffice to show that our moorland heaths are 

 well-fitted to endure great cold. Ling extends far within the 

 Arctic circle, though it seldom covers large surfaces there, and it 

 rises to 2000 metres (6600 feet) on the north side of the Alps It 

 extends southward to the shores of the Mediterranean. Our 

 large-flowered heaths have not been traced quite so far north as 

 ling, and they are not found on the Alps, though they inhabit 

 the Pyrenees. Many representatives of the heath family, with 

 like structure of leaves, are found in the extreme north of the 

 American continent. Those features which assimilate our heaths 

 to desert-plants, and which seem to be obvious adaptations to a 

 situation of extreme drought, are equally serviceable to plants 

 which have to face boisterous winds and low temperature. The 

 shrubs of the far north are low, tufted, small-leaved, evergreen, 

 and dry — just like the heaths of our moors. Middendorfif ^ shows 

 how the Dahurian larch becomes stunted in proportion to in- 

 creasing cold. Before it disappears altogether, it is cut down to 

 a prostrate, creeping shrub. One such dwarf larch, though 150 

 years old, was only a foot or two across. Plants much exposed 

 to biting winds must make the most of any shelter that can be 

 had ; their branches push out timidly, and for a very short 

 distance ; the leaf-surface is reduced to a minimum ; since the 

 warm season is short, evergreen leaves are profitable, for 

 they enable the plants to take advantage of early and late 

 sunshine. 



The heaths and many other moorland plants bear the marks 

 of the Xerophytes, or drought-plants. Xerophytes grow under a 

 considerable variety of conditions, some of which do not suggest 

 drought at first sight, but their tissues are always ill-supplied 

 with water. It may be that water is not to be had at all, as in 

 the desert ; or that water must not be imbibed in any quantity 

 because of low temperature, as in Arctic and Alpine climates ; 

 or that the water is mixed with useless and perhaps injurious 

 salts, from which it can only be separated with great difficulty, 

 as in a salt-marsh. Whatever may be the reason for abstinence, 

 xerophytes absorb water slowly, part with it slowly, and endure 

 drought well. 



In the case of moorland plants there is an obvious reason 

 why many of them, though not quite all (Sphagnum is one 

 exception) should rather thirst and grow slowly than pass large 

 quantities of water through their tissues. The water contains 

 hardly any potash or lime, and very little that can aid the 

 growth of a plant. But it is probable that this is not the sole 

 reason. Except where special defences are provided, it is 

 dangerous for a plant which may be exposed to wind or low 

 temperature to absorb much water. 



(7b be continued.) 



INDIAN COALS AT THE IMPERIAL 



INSTITUTE. 



'T'HE Imperial Institute has been subjected to much adverse 



criticism. Its commercial collections, refreshment catering, 

 fellows' club, limelight lectures by eminent men, continental 

 orchestras, library, exhibitions, journal, and commercial intel- 

 ligence department have all in turn been disparaged. The 

 scientific and technical department has alone escaped attack. 

 There, in well-equipped laboratories, with an enthusiastic staff 

 of experts, valuable research work on new products has been 

 carried on quietly and continuously for some years past. A 

 striking example of the value of the work done is afforded by 



1 Examples are quoted by Warming, Lehrb. d. okol. PJlanzengeographie, 

 p. 198. 



2 " Sibirische Reise," vol. iv. p. 605. 



NO. 1503, VOL. 58] 



the exhaustive report just published on the coal supply of India 

 by Prof Wyndham R. Dunstan. This report eml^odies the 

 results of the examination of a large number of selected samples 

 from the principal seams. Methodically arranged, well printed, 

 and written in a style that is not too abstruse for the general 

 reader, it is a model of what such a report should be. 



The examination was undertaken at the instance of the 

 Government of India. The results are shown in a tabular form, 

 and the chief points in connection with the occurrence, dis- 

 tribution, production and character of Indian coal are sum- 

 marised. Unlike the English and Welsh coals, the Indian 

 coals are chiefly of Upper Palaeozoic and Lower Jurassic age. 

 They are widely distributed, and only a small portion of the 

 known coal area is as yet worked. The increase in coal pro- 

 duction in India of late years is very remarkable, and, as the 

 household consumption is inappreciable, practically the whole 

 output is used for steamships, railways, and factories. The 

 output for 1896 was as follows : — 



Tons. 



Assam i77.3Si 



Baluchistan 10,572 



Bengal 3,037,920 



Burma ... ... ... ... 22,993 



Central India 115,386 



Central Provinces ... ... ... 141,185 



Nizam's dominions 262,681 



Madras) 



Punjab) 79,925 



Total 



3,848,013 



The results of the examination of the various coals have been 

 plotted in curves, and a table of previous analyses of Indian 

 coal is also given. The coals vary greatly in composition and 

 in quality. Most of them are quite suitable for ordinary pur- 

 poses, whilst some of the samples from Bengal and Central India 

 are of excellent quality, quite equal to that of many English 

 or Welsh coals. Among the many samples described are two 

 from Hyderabad, which are of fair quality. Neither of the 

 samples, however, gave such good results as those recorded by 

 Mr. Tookey in Mr. J. P. Kirkup's monograph on the Sin- 

 gareni coalfield, published in the Transactions of the Federated 

 Institution of Mining Engineers in 1894 (vol. vi. pp. 421-448). 

 This valuable memoir appears to have escaped Prof. Dunstan's 

 notice in drawing up his useful list of works of importance in 

 connection with Indian coal. The Bengal coal is that most 

 largely mined, and a great deal of it is a serviceable steam-coal. 

 Many samples cake well, and contain but little sulphur. The 

 coke made from this coal appears, therefore, to be suitable for 

 iron-making. In view of the occurrence of rich deposits of iron 

 and mangane.se ores in India, this is a matter of great import- 

 ance, for, owing to difficulties connected with fuel supply, the 

 records of iron manufacture in India have been disastrous. 

 Attempts to manufacture steel in Southern India were made in 

 1818, in 1830, in 1833 and in 1853, but in each case the want 

 of suitable fuel was an unsurmountable difficulty. Charcoal was 

 exclusively used ; and in order to supply one blast-furnace it was 

 necessary to clear no less than two acres of moderately heavy 

 forest per day. For every ton of charcoal made, five tons of 

 wood were consumed. The information contained in Prof. 

 Dunstan's report should therefore show that the difficulties in 

 the way of creating an Indian iron industry presented by the 

 fuel supply can easily be overcome. Indeed, the supply of coal 

 is so enormous that this report should be the means of directing 

 attention to the possibilities of many other branches of industrial 

 enterprise. Bennett H. Brough. 



THE INTERNATIONAL AERONAUTICAL 

 CONFERENCE} 



npiIE second meeting of the International Aeronautical Com- 

 -*■ mittee (which was appointed by the Paris Meteorological 

 Conference of 1896) was held at Strassburg, Germany, March 

 31 to April 4, inclusive. Besides the President, Prof. lier- 

 gesell of Strassburg, and the Secretary, M. de Fonvielle of 

 Paris, there were present the following members of the com- 

 mittee : Messrs. Cailletet and Besan9on of Paris, Assmann and 

 Ber.son of Berlin, Erk of Munich, Rykatcheff and Kowanko of 



1 By A. Lawrence Rotch. (Reprinted from the U.S. Monthly Weather 

 Review for April.) 



