428 



NATURE 



[June 9, 1910 



experiment has also shown that it would be better to pre- 

 serve one or two hundred hailstones separate from each 

 other than a greater number of them, but partly — especially 

 in lower layers — frozen together. That can be attained 

 by placing the hailstones in some very viscous liquid {_e.g- 

 cylinder-oil, vaseline, or castor-oil) of a density nearly equal 

 to that of hail. 



For the investigation of the microstructure of a separate 

 hailstone Mr. W. Dudecki and I made a thin section of it 

 by first rubbing one side on emery-paper or by melting it 

 with the warmth of a finger. This side was laid upon an 

 object-glass and frozen to it, after touching for some time 

 with a finger the other side of the glass. The other side 

 of the hailstone was then polished in the same manner as 

 the first until the requisite thickness was attained. These 

 operations were made in free air, and were so much easier, 

 as the temperature of the air was below o°. Still, it 

 was found possible to grind hailstones in the laboratory 

 at the temperature of the room by means of cooling the 

 object-glass, the emery-paper, &c., in double-walled vessels 

 with a mixture of ice and common salt. 



For the optical investigation of thin sections in free air 

 a polarising microscope was used, and in a lecture-room 

 a projecting lantern. In the latter case (Fig. 2) the section 



Fig. 2. — L, Projecting lantern ; r, polariser ; m, mirror ; r, refrigerating 

 veasel ; o, objective ; A, analyser. 



was laid in a refrigerating vessel with double walls and 

 double bottom (to avoid the condensation of aqueous vapour 

 from the surrounding air) of plane-parallel glass plates. The 

 space between the walls contained a mixture of ice and 

 common salt. The real image of the section was thrown 

 on a screen or on a photographic (" Autochrom ") plate. 



The greater part of the hailstones were crystalline 

 individuals, as also was the case with " artificial hail- 

 stones " — drops of water frozen in a mixture of cinnamon 

 and linseed oil of suitable densit}-. In those hailstones, 

 which consisted of several crystalline individuals, there was 

 no regularity in the form of the boundaries between 

 cr3'stals, or in the angles between these boundaries, or in 

 the directions of the optical axes, which lay indifferently 

 to each other, as well as to the milky nucleus of the hail- 

 stone, which appeared in the section as a number of air- 

 bubbles of different size. 



I trust that my attempt will cause similar researches to 

 be undertaken, and I should be very glad if anyone who 

 may be able to preserve or study larger or more peculiar 

 hailstones than I have hitherto dpne will do so, and in this 

 way improve our deficient knowledge on the origin of hail 

 and the details of its formation. Boris Weinberg. 



The Physical Laboratory of the Technological 

 Institute of Tomsk, Russia. 



Thoughtless Destruction of Wild Flowers. 



May I ask through your widely circulated paper that those 

 who organise the weekly or fortnightly visits of poor town 

 children to country villages may be requested to instruct 

 these children to pluck only a limited number of wild 

 flowers? It is no uncommon sight to see a dozen or more 

 of these children going along a road or railway embank- 

 ment and plucking every flower they can find, as well as 

 rooting up those which are small enough. In half an 

 hour the flowers have withered, and are thrown away, when 

 the same process is repeated. Geo. Henderson. 



Otfprd, Kent, May 27. 



NO. 2 1 19, VOL. 83] 



RECENT PROGRESS IN INDIAN FOREST 

 TECHNOLOGY. 



THE excellence of the work of any public depart- 

 ment depends on the character and ability of 

 the men who direct it, and the Indian Forest Depart- 

 ment was singularly fortunate in its first Inspector- 

 General, the late Sir Dietrich Brandis, K.C.I.E., 

 F.R.S. He secured State ownership and State 

 management for the forests both in British India 

 and in the native States, and also a trained staff of 

 forest officers. He placed Indian forest law on a 

 firm basis by selecting as Conservator of Forests, Mr. 

 B. H. Baden-Powell, C.S.I., a member of the 

 Punjab Civil Service, who, after working for a decade 

 of his life in the forest service, became presiding 

 judge of the chief court at Lahore. Baden-Powell 

 drafted the Indian Forest Acts, models of forest law 

 that are followed by all colonial legislators, and his 

 " Manual of Forest Jurisprudence " is the only Eng- 

 lish book on the subject. No mere forester could 

 have drafted those laws successfully, nor could any 

 mere lawyer, but Baden-Powell was both lawyer and 

 forester. 



Brandis also established a forest survey under Lieut.- 

 Colonel F. Bailey, R.E., and Mr. W. H. Reynolds, and 

 their maps gained gold medals at two Paris exhibi- 

 tions, and were the first Indian maps that showed 

 a good system of contour lines. A forest school for 

 training native members of the provincial and execu- 

 tive staffs of the Forest Department was established 

 in 1881, at Dehra Dun. Useful manuals of forestry, 

 by Mr. E. E. Fernandez, and of botany, were pub- 

 lished soon after the establishment of this school for 

 the use of the students. Brandis also published a 

 Forest Flora of Northern India, followed quite re- 

 cently by his last great work, "Indian Trees," 

 a forest flora for the whole of India. Mr. Kurz had 

 previously written one for Burma and Major Bed- 

 dome for Madras, while Mr. J. S. Gamble, C.I.E., 

 F.R.S. , published a splendid monograph of Indian 

 bamboos. Gamble, under Brandis's direction, pub- 

 lished, in 1881, a "Manual of Indian Timbers," and 

 again, in 1901, after collecting material for twenty 

 years, a new and greatly enlarged and improved 

 edition. "The Indian Forester" first appeared in 

 1876, Dr. Schlich, now Sir W. SchHch, K.C.I.E., 

 F.R.S., being the first editor. Schlich succeeded 

 Brandis as Inspector-General of Forests in 1881, and 

 instituted a proper system of working plans for 

 Indian forests. He came home in 1885 and estab- 

 lished a school of forestry at Coopers Hill, and, in 

 conjunction with myself, published a " Manual of 

 Forestry." 



The training of men in England for the Indian 

 Forest Service was not at first in accordance with the 

 wishes of Brandis and Schlich. They recom- 

 mended that the Imperial School of Forestry 

 should be at an English university, and that, 

 as the so-called Civil Service of India is re- 

 cruited chiefly from university men of good 

 literary and legal attainments, so the Imperial Forest 

 branch of the Civil Service, which manages one- 

 quarter of the land of British India, should be com- 

 posed of university men of good scientific attain* 

 ments. But the India Office wished to support th«| 

 Royal Indian Engineering College at Coopers Hilli 

 and kept the forest probationers there until 1905, thjj 

 year before the college was closed. In 1905, a^ 

 Imperial School of Forestrv was established 

 Oxford under Sir William Schlich, and is now trail 

 ing more than seventy men for India, the coloniesj 

 and for forest work at home. 



Until 1904 very little progress was made in Indiaij 

 forest technology, for which Brandis had laid such 



