10 BULLETIN 644, U. S. DEPARTMENT OF AGRICULTURE. 



ADVANTAGES OF USING SAMPLES OF STANDARD WEIGHT. 



By the use of a balance such as that just described, the sample is 

 standardized and the work of ascertaining the lint percentage re- 

 duced to two entries in the records, the name of the selection and the 

 percentage of lint, and all calculations have been avoided. 



The use of the standard sample of seed cotton has other very mate- 

 rial advantages. It will be shown that the adoption of the standard 

 sample simplifies the methods of calculating lint indexes and the 

 weights of seeds, that the number of seeds of a standard sample is a 

 direct indication of their size, and that tables may now be prepared 

 by which planters without special apparatus may ascertain the lint 

 index of a variety. 



METHODS OF CALCULATING LINT INDEXES AND SEED WEIGHTS. 



Having used the standard sample of 100 grams of seed cotton and 

 determined the percentage of lint, which, as has been seen, is the 

 actual weight of the lint, the lint index and the weight of the seeds 

 per hundred may be obtained from the data in hand by the use of 

 the following formulas: 



Percentaee of lint 



Number of seeds in specimen 

 Percentage of seed 



X 100 = lint index. 



X 100 = weight of 100 seeds. 



Number of seeds in specimen 



The lint index may also be determined in the following manner. 

 If a sensitive balance is to be had, the weight of 100 fair average 

 seeds fairly ginned should be secured by actual weighing, or, better, 

 the average weight of two lots of 100 seeds should be secured. The 

 following formula may then be used to determine the lint index : 



Wetejht of 100 seeds w .. .. . , 



^ - 2 j X lint percentage = lint index. 



Percentage ot seed ' 



NUMBER OF SEEDS IN A STANDARD SAMPLE AN INDICATION OF 



THEIR SIZE. 



In the absence of a balance sensitive to the hundredth of a gram, 

 on which such small lots of seeds as 100 may be accurately weighed, 

 the use of the standard specimen of seed cotton has another ad- 

 vantage in that the number of seeds in the specimen may be taken 

 as a direct indication of their size, and the weight of the seeds 

 per hundred may be found by reference to Table TV. This table 

 gives a list of the numbers of seeds in standard specimens of 100 

 grams of seed cotton, calculated for various percentages of lint and 

 weights of seed per hundred. 



