195 



fact, it is quite short. It could not be used, for example, in thread, , 

 bands, or any fine pure gum goods. In solution it loses its tenacity- 

 very quickly, so that it would not do for high grade cements. 

 Another thing about it is that it softens with age, whereas the Para 

 rubbers grow hard and oxidize. Wc think the reasons for these 

 differences are two : one being found in the manner of coagulation, 

 which does not seem equal to the smoking process ; and the other 

 being due to the undoubted change wrought upon the tree by a 

 different climate from that in which the tree naturally flourishes. 

 It is to be understood, of course, that the rubber is valuable, and 

 will find a ready market at a good price, but it is not the equal of 

 either fine or coarse Para. We think this is another proof that 

 rubber will be cultivated most successfully in the regions where it 

 grows wild. 



CORRESPONDENCE. 



To the Editor, 



Agricultural Bulletin. 



Dear Sir, — Reading the notes on the value of Incidental Incre- 

 ment of Plant food in Soils in the last issue, I am inclined to add 

 the following note on the same subject. There is nothing new 

 in it nor am I confident that it deserves publication, 



I remain, 



Yours sincerely, 



V. K. MEARON. 



j 8th Decembei', igoi . 



Incidental Increment of Plant-food in Soils. 



The rapid decomposition of organic matter in Tropical Soils 

 tends to keep the nitrogenous portion of the plant-food in them 

 at a minimum, and analysis often shows a comparatively low per- 

 centage of nitrogen. But Nature herself, as if to compensate for 

 the rapid decomposition of organic nitrogenous matter, has pro- 

 vided the Tropics with an increased number of species of Legu- 

 minous plants especially of Papilionaceous Sub-order. The roots 

 of these plants serve, through the agency of minute organisms 

 that live in the roots and the soil, as a medium for rendering 

 atmospheric nitrogen available to plants. Though this theory is 

 pretty recent the importance which leguminous crops possess as 

 valuable fertilizers of soil has long been recognized by farmers, 

 both in the East and the West. Hence the invariable rule of 

 inserting one or more leguminous crops in a System of Rotation 

 of crops. But we are not generally aware of the full importance 

 of the part played by leguminous crops in the incidental incre- 

 ment of plant-food in soils. Either in forests, plantations, gardens 

 or even on waste lands, many of the plants which are classed as 

 weeds are important means of nourishing the soil. Leguminous 



