304 



DR. L. H. GOUGH. 



evident that percentage lint has not been greatly influenced, if at all, by the pink 

 bollworm. The reduction of the magnitude of the standard deviation, however, 

 may be considered to be connected with the greater purity of AfE.fi as compared with 



Mitaffifi.* 



T^ble XVI. Variations of the Percentages of Lint in Mitaffifi and Affifi Cottons ginned 



by the State Domains during the years 1891-1917, calculated from figures supplied 



by the State Domains Administration. 



Year. 



Mitaffifi 

 Sakha 



Qorashia 



Year. 



Mitaffifi 

 Sakha 



Qorashia 





Ginnery. 



Ginnery. 





Ginnery. 



Ginnery. 



1891 



330 



33 7 



1908 



34-0 



35-9 



1S92 



— 



— 



1909 



330 



34-2 



1893 



34-0 



35-5 



1910 



33-0 



34-9 



1894 



33-3 



34-9 



1911 



33-7 



349 



1895 



333 



35-2 



1912 



34-9 



— 



1896 



33 3 



35-5 



Mean 



34'0 



35-3 



1897 



34-9 



35-2 





3 = 



0-74 



1898 



35-5 



35-9 



■Affifi 



33-9 



34-1 



1899 



349 



36-2 



1911 



33-9 



. — 



1900 



34-9 



34-9 



1912 



34-5 



34-5 



1901 



34-6 



34-9 



1913 



34-0 



— 



1902 



34-6 



35-9 



1914 



34-0 



— 



1903 



34-9 



37-1 



1915 



33-3 



— 



1904 



33-3 



35-5 



1916 



34-5 



._... 



1905 



33-7 



34-9 



1917 



33-7 



. — 



1906 



34-0 



35-5 



1917* 



34-1 



34-3 



1907 



33-7 



35-2 



Mean 



3 = 



0-36 



* Special experimental cotton. 



Note. — It is not explained what difference is supposed to exist between Mitaffifi and 

 Affifi ; the names are in general application synonymous. — G. C. Dudgeon. 



Finally, nowhere do the deviations observed reach three times the standard 

 deviation and perhaps they may not have any real significance. 



Table XV, in which the percentages of lint for various varieties for the period 

 1911-1917 are recorded, just covers the period during which Gelechia has risen from 

 insignificance to importance. It can here again be pointed out that none of the 

 fluctuations shown is sufficiently large to be significant. 



Finally, comparing the standard deviations for the annual variations in the 

 percentage lint, as shown in the two tables under discussion, with the standard 

 deviation found for the samples composing the crop of a single field, shown in Table 

 XIV (comparison of sound and attacked samples), it will be seen that the standard 

 deviation of the annual variation is nearly the same as the standard deviation of the 

 variation of the percentage lint of various parts of a single crop. 



£. Calculation of the Damage done by the Pink Bollworm. 



The damage done to the cotton crop can be estimated, in view of what has been 

 said above, and the quantity lost can be distributed with considerable accuracy to 

 each of the sources of loss described. 



*See note at foot of Table XVI.— G.C.D. 



