RANGE AND CLIMATE 27 



per acre ; the next highest figure is from Reunion 16 and only amounts to 

 6 24 Ibs. per acre. In great contrast to these figures are the minima recorded 

 from East Java 16 and amounting to only 1-13 Ibs. of ammoniacal and 075 

 Ib. of nitric nitrogen. In one and the same place also there are large yearly 

 variations. Thus, in Tonkin during the years 1902-08 the ammoniacal 

 nitrogen varied from 3-25 to 1470 Ibs., and the nitric nitrogen from 3-95 

 to 13-60 Ibs. It follows, then, that no definite figure can be given, as the 

 quantity received may vary from 2 to nearly 30 Ibs., the probable amount 

 being in the neighbourhood of 10 Ibs. Whereas the ammoniacal nitrogen 

 is derived from the degradation of organic matter, notably that contained 

 in the sea, that which occurs as nitric may be largely the result of atmospheric 

 electrical discharges ; this connection, after having once been accepted and 

 then discounted, has received support by Capus 17 following on a study of 

 results obtained by Aubray 18 in Tonkin. 



The main effect of drought on the cane crop is, of course, reduction in 

 tonnage ; what crop is harvested will contain a high percentage of fibre 

 due to the restricted length of the internodes, and to the evaporation of 

 water from the cane by increased transpiration. 



The humidity of the atmosphere is another factor that bears on crop 

 production, and as it grows less the greater becomes the quantity of water 

 that is transpired from the leaves, and the greater becomes the demand on 

 the soil supply. Early writers observing that the bulk of the cane culti- 

 vation was near the coast attributed a specific effect on the cane to the 

 saline breezes and maritime climate. 



Thus Wray 19 writes : 



" The climate most congenial to the cane is of a warm and moist character, 

 with moderate intervals of hot, dry weather, attempered by the refreshing sea 

 breezes. It has been found to grow most luxuriantly on islands and along the sea 

 coasts of the mainland, which leads us to conclude that the saline particles borne 

 on the sea breeze exercise a powerful effect on the growth of the cane." 



Delteil 14 expresses himself in terms similar to those used by Wray : 



" The sugar cane originating from India and Eastern Asia demands a warm, 

 moderately moist climate, with intervals of dry heat ; it loves sea breezes because 

 of the particles of salt which are carried to the fields and increase their fertility." 



According to Boname : 15 



" A warm and moist climate is most favourable to the growth of the cane, 

 and it is on islands and the sea coast that the most luxuriant plantations are to 

 be seen, for it is here that are found together the conditions of heat and moisture 

 demanded for its greatest development." 



Stubbs, in commenting on this idea, is most certainly right in attributing 

 the maritime position of many sugar plantations to economic reasons. 

 An inland sugar estate in most tropical countries would be deprived of means 

 of access to the world's markets. Where a local market exists, the cane is 

 grown successfully in districts remote from the sea, as in Queensland, Argen- 

 tina, Brazil and India. Some insular districts, such as the arid parts of the 

 Hawaiian Islands, have a climate of low humidity, and the same is also the 

 case in the dry parts of Peru, both of these places producing, under irrigation, 

 the largest crops on record. 



A factor that has influence on the composition of the cane is that of direct 

 sunshine as bearing on the process of change known as photosynthesis. 

 The experiments of Went in Java are referred to in Chapter I, and the factor 

 may reasonably be of some moment in the wetter districts, and may account 



