160 PERIODICITY IN THE GROWTH OF SUGARCANE 



sheaths rapidly diminish in length owing to the immaturity of the joints, we 

 have the following differences in the length of leaf sheaths. The average 

 difference in length of adjoining leaf sheaths, in the shortest cane, is 0'44", and 

 the five greatest differences are Vi", O'T", 0-7", O'T", and 0-6". In the longest 

 cane, the average difference is 0"59", and the five greatest are TS", r4", 1*3", 

 rS", and 1"1". Compare with these figures those obtained from the three 

 examples, given by Kamerling, of thick canes grown in 'Java : — 



(1) Average difference 0-11", the five greatest being 0-3 , 0-2", 0-2", OJ", 0-1". 



(2) „ 0-23", „ 0-6", 0-4", 0-4", 0-4", 0-2". 



(3) „ 0-02", „ 0-1",'0-0",0-0",0-0",0-0". 

 It appears from this that it might be well for Kuijper's work to be done 



again in a series of indigenous Indian canes, and, until this is done, it is unsafe 

 to use the Java method for the accurate measurement of gro^\•th in length of 

 young internodes by merely observing the distances of successive transverse 

 marks. 



Taluqdar's measurements extended from May to early November, but 

 as the period of tillering was not completed until the beginning of June, the 

 earlier measurements only refer to a small number of shoots, while at the 

 end of the season very many had been destroyed by moth-borers. Five or 

 six months may be taken as the period of active gro^^i:h, and this received 

 an enormous impetus in July when the rains set in, thus presenting great 

 similarity with the course of events already referred to in Louisiana. An 

 attempt is made to determine the influence of temperature and moisture on 

 growth, and the general conclusion arrived at is that these two factors act 

 in common and that, as soon as one of them declines, the effect of the other 

 is neutralized. In the tables it is seen that the period of growth is limited 

 at both ends by declinijig warmth and moisture. Growth in the tropics is 

 very different from that in Louisiana and North India, in that the temperature 

 there never sinks so low as to be ineffective and, when moisture fails, irrigation 

 is resorted to. The usual period of groA\'tJi is twelve months and, consequently, 

 larger crops are obtained. 



II. The method of cane jmeasurements adopted and the iMaterial us>ed. 

 The method adopted in this paper is altogether different from those 

 referred to above. It is, namely, to take the cane at crop time and measure 

 the parts, and from these measurements to try and infer the geneial gro^^i;h 

 conditions at the place where the crop was grown. The length and tliickness 

 of the different organs vary much in different places, and, from their study, 

 it is attempted to form an opinion as to the relative suitability of such places 



