Correspondence. 510 [Dbc> 190 gj 



Peninsula with the object of reducing malaria, the estimate was prohibitive The 

 Government distributes quinine to all school children and malarious villagers 

 as a prophylactic which has some measure of success ; directions how to combat 

 malaria have been widely distributed in the vernacular, The only thing is 

 for the general public to be educated in the ways of battling that disease as much 

 can be done by individuals, but the large question of drainage is one for the 

 Government, and in my opinion it is too vast to cope with." 

 November 21st. 



Capillary Tubes. 



Syston, Ukuwella, 24th November, 1806. 

 Dear Sir,— In reference to the extract from the London " Times" which I 

 enclose, I should be glad to know if the " capillary tubes" mentioned in it are (as one 

 would imagine) merely air spaces, or whether I am mistaken. 



I am, dear Sir, yours faithfully, 



W. H. BIDDULPH. 



Extract referred to from a recent number of" The Times." 1 

 In quoting from a technical writer last week we gave a passage in which the 

 word " mulch" occurred, and we have been asked what is the exact meaning of this old 

 English term. It is curiously ignored by the dictionaries, though every peasant uses it, 

 and probably most farmers. Very roughly speaking, it is that light caking of surface 

 soil which protects the moisture beneath, and to mulch is to beat stuff together into a 

 compost without binding it too tightly. The whole matter, however, is of such 

 practical importance at a period following a long spell of dry weather that the 

 history of the whole matter, as officially set forth by the text-book of the Royal 

 Agricultural Society, is well worthy of being given here. It must be premised, that 

 if surface soil is frequently stirred, kept loose in fact, moisture in the subsoil natur- 

 ally travels up towards it- 



" When rain falls upon the soil, some of it sinks down to replenish the stores 

 below ; but during the period of active growth, and particularly in a droughty season 

 there is a movement of moisture from below upwards. The moisture replaces that 

 lost at the sui'face by evaporation ; and its direction is such that it tends to keep the 

 soluble plant food where it is wanted, that is, about the roots of the plants. If 

 enough water be poured into a saucer in which stands a flowerpot full of earth the 

 surface of this mould will at length become moist, the water having travelled 

 upwards by capillarity. But here another point has to be considered. If all the 

 capillary tubes are open to the surface evaporation can proceed from them so freely 

 that the underground store of moisture may be insufficient to supply the continuous 

 demand. Hence again it is desirable to keep the surface soil, by frequently stirring, 

 in such a state that the capillary tubes are broken, or interrupted a little below the 

 surface. In this case the mere superficial covering of mould acts as a soil mulch, and 

 like a layer of leaves of grass or farmyard manure, it protects the moisture beneath." 

 [The " tubes" are evidently the air spaces between the particles of soil.— Ed.] 



ANT-HILL EARTH. 



Sir,— In the October issue of the Tropical Agriculturist* , a correspon- 

 dent inquires to what uses the earth of white-ants is put, apart from its general 

 use, mixed with cowdung for the floors of Sinhalese villagers' houses, for plugging 

 up rat-holes in walls and floors, and for plastering mud walls, to which it gives 



'Page 347, Vol. XXVII, October, 1906. 



