119 



Turning to methods in use in the West Indies we find an 

 extremely helpful article in the Agricultural News for May 1916. 

 Here the writer brings out very forcibly the value of uniformity of 

 method. Thus : 



" It is thought that were there more uniformity of methods 

 amongst investigators, there would in all probability be much better 

 agreement as regards results. There has been too strong a tendency 

 in the past to lay out manurial experiments according to personal 

 ideas rather than to scientific ideas. 



" With present methods the truth about the effects of manures 

 on trees can be more usefully expressed in words than in numbers ? " 



This latter fact is as true as it is desirable that it be changed. 

 If investigation has not gone far enough to provide data sufficiently 

 precise on which to base actual yield experiments, then it is our task 

 to initiate work which will have that end in view. The way may be 

 long, but it will undoubtedly pay in the long run. 



As concerns the method in use in Trinidad and Nevis, both of 

 which are outlined on the article quoted, to which attention is 

 strongly urged, it appears that they also cannot be expected to 

 produce accurate results. The two methods are given as follows : 



(1) Trinidad- 

 Gain or loss = ((Vi-Vj) - (C,-C,)]-m 



Where Y ■^ = value of yield from manured plot, 



say 1915-16. 



V,, = value of yield from manured plot, 



say 1914-15. 



Cj = value of average yield from two control 

 plots, say ... ... ... 1915-16. 



Cg = value of average yield from two control 

 plots, say ... ... ... 1914-15. 



m = cost manuring. 



(2) Nevis- 

 Gain or loss = value of [{n + (nj— Hi)} — c] — m 



where n = average number of nuts per tree picked 

 between two annual applications of 

 manure. 

 Hj^ = average number of nuts per tree picked at 

 beginning of experimental year. 



7*2 = average number of nuts per tree picked 

 • at end of experimental year. 



c = the n + Qii^ — ^i) value of the control. 



