290 



DR. L. H. GOTJGH. 



second record was made during April, and shows the effect of rising temperature 

 caused by the setting in of a spell of hot weather accompanied by a " Khanisin " wind. 



X.'l2 4 S 6 I0M T 2 4- 6 3 IOXIl2 4 6 8 I0M T 2 4 6 8 10 XII 2 4 6 8 lOM^ 4 6 S I0XI|2 4 6 8 I0M T 2 4 6 6 10X11 





























































































































































































































































































































































































Fin 





























































































































































































































































































































































































40 









— 



— ■*• 























-v 



















^ 









_ 



L_ 





































30 













































- 



























- 











^. 

















































































































































































































































































































































































































^0 





























































































































































































































































































































































































































































1 





























Pig. 2. Pall in humidity (solid line) and consequent fall in weight of the cotton-seed 

 (broken line) due to the effects of " Khamsin " wind. 



Having shown that the weight of cotton seed is relative to the temperature 

 and to atmospheric humidity of a few hours previous to the time of weighing, it 

 only remains to remark that when the results of several weighings made over an 

 extended period of time and from different samples are combined together, it 

 may be assumed that the deviation of the combined figures will be smaller than 

 that of any one weighing ; and as the errors introduced by the varying conditions 

 are unbiassed, the figures will then be more nearly correct for average humidity 

 and temperatures. The more numerous the samples combined, therefore, the 

 smaller the resultant probable error for average conditions. 



Examining Table VII we find that the average weight of a given number of 

 sound seeds (in this case 1,000) falls steadily as the percentage of Gehchia attack 



Table VII. Comparing Intensity of Gelechia Attack ivith Weight of Sound Seeds. 



Number of 



Percentage of 



Total 



Total 



Average weight 



samples 



sound seeds 



number of 



weight of 



of 1,000 



used. 



in sample. 



sound seeds. 



sound seeds. 



sound seeds. 



1 



100-0 



1,499 



178-0 



1187 



56 



97-0 



83,872 



9,631-9 



114-8 



28 



92-1 



36,407 



4,037-5 



110-9 



44 



86-9 



45,338 



4,820-6 



106-3 



22 



81-9 



19,106 



1,947-8 



101-9 



26 



77-5 



27,384 



2,774-6 



101-3 



28 



72-2 



27,137 



2,744-2 



101-1 



13 



66-6 



12,438 



1,249-5 



100-5 



20 



62-2 



14.112 



1,390-9 



98-6 



15 



56-5 



7,989 



746-0 



93-4 



8 



51-5 



5,439 



452-7 



83-2 



8 



47-4 



4,745 



4127 



87-0 



4 



41-5 



1.989 



161-4 



81-1 



5 



37-4 



1,955 



171-6 



87-8 



2 



32-2 



504 



41-9 



83-1 



2 



27-7 



480 



37-7 



78-5 



The samples each consisted of 100 bolls of Sakellarides. 



Each pair of variates weighted according; to the number of samples composing it, 



2 I - r 2 

 In the computation of the probable error, n in the formula P.E. = 2 — has not been 



weighted; correlation r= 0-976 ± 0-008. 



