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( 95 ) 



Practically however I hardly believe that the above distinctions can be adopted by the 

 forester, and there are some difficulties in arranging the various rocks in India according to 

 such a system. This difficulty is still increased in excessive tropical climates, where many 

 eugeogeneous rocks may be dysgeogeneous according to the degree of atmospheric humidity 

 which prevails. For a practical understanding of influences of this nature, the subject may, I 

 think, be greatly simplified, if the distinction of mechanical and physical permeability,* 

 as noted in former pages, is made. According to this we would obtain the following eons-' 

 pectus which, in its principles, is the same as Thurman's : 



Easily decomposing or eugeogeneous. | J" g^rmeable rocks (pelogeneous.) 



[ ^- -tl-aii permeable rocks (pelopsammogeneous.) 



Noteasilydecomposing,ordysgeogeneous. f ?\ Impermeable (of course to a certain degree 

 J r o' J o o ^ only) rocks (psammogeneous.) 



There are, however, certain cases, as, for example, some calcareous sandstanes, where the 

 rocks, although impermeable under certain circumstances, are comparatively easily decom- 

 posed : this depends upon the component parts of the rock. 



Amongst half permeable rocks, we may include all those composed of permeable and imper- 

 meable constituents, the former of which will decompose into indefinitely divided particles (soil) 

 while the latter will remain unchanged in the shape of angular detritus or pebbles, as is the case 

 with many granites, and schistose rocks, also with many coarse sands and conglomerates, when 

 mixed with fine permeable soil or cement. These half permeable rocks and soils are the most 

 favourable to tree vegetation, especially if rich in alkalies ; but if they are of a more silicious 

 or calcareous nature, as are certain breccias, coarse sandstones, etc., they may be in the same 

 degree infertile and sterile. All depends here again upon the chemical nature of the cement. 



The surface soil is of somewhat less importance to the forester, and is chiefly taken into 

 account, when plantations are formed. Here of course porosity has first to be considered 

 and then chemical composition and colour. The knowledge of the thickness of the surface 

 layer is also important, as upon this the shape and growth of trees depend. In heavy and 

 stiff soils seeds will not germinate, except at very small depths, probably never exceeding 2 

 inches on an average : but in very porous light soils, they may, as expei-ience teaches us, ger- 

 minate under circumstances at a depth of 1 to 1^ feet. However, seeds as they are shed in 

 the jungles rarely become more than covered by earth, and this is chiefly effected by the 

 action of rain. Yery minute seeds may become imbedded in the earth by heavy night 

 dews. 



For a more correct knowledge of the qualities of surface soils, I must refer to the experi- 

 ments and scales of Schuebler,t which, if I am not mistaken, are generally adopted by agri- 

 culturists. 



3. Collecting and drying of botanical specimens.'^ 



The collecting and drying of plants is so simple that one must feel surprised at finding 

 any of the foresters in India unacquainted with the process. Boys of 8 to 10 years age 

 under my charge used to learn the art of drying plants in less than 2i hours' time, and even 

 the Burmese peons who accompanied me on my travels required hardly more time. I think 

 foresters in India ought all to be acquainted with the process, so as to enable them to for- 

 ward proper specimens when they wish to consult botanists as to the name of a plant unknown 

 to them. 



I will give a few hints, but these remarks are intended only for practical foresters, and 

 therefore refer only to trees and woody plants which (with a few exceptions such as arbo- 

 reous Euphorbias and mangroves) usually are of rather a dry nature, and therefore easy to 

 manage. I do not think it necessary to give instructions for drying orchids and other fleshy 

 or saline plants that are difficult to deal with. Those who wish to make themselves acquain- 

 ted with this process will find the necessary information in the books above cited. 



For collecting plants in tropical countries, the botanical tiu-bbx is of little use. Accord- 

 ing to circumstances and climate, baskets covered with cool plantain or colocasia leaves, or 

 portfolios of paste-board, containing drying paper, are preferable. It is very convenient to 

 have a peon at hand, carrying such a portlblio, or a pair of paste-boards, containing two or 

 three quires of paper. Many plants, such as bamboos, etc., especially during the hot season, 

 would not keep fresh up to the time of their arrival in camp, and must therefore be put as 

 soon as possible between paper. 



Permeability can roughly be tested simply by allowing a drop of water to fall on the rock ; the quicker 

 the drop disappears, the (greater is the permeability. 



f Schuebler, Grundsuetze der Agricultur-cbemie. 



t I would refer those who wish to make themselves more intimately acquainted with the collecting and dry- 

 ing of botanical specimens to : 



G. Beiitham s Outlines of Botany, and Oliver's First Book on Indian Botany. 



Both these booka are instructively and plainly written, especially the former, and the latter ought to be 

 intelligible to every grade of forester, even to the more intelligent natives. 



