METHODS OF INVESTIGATION 181 



Ginning Out-turn. The determination of this ratio of 

 lint to seed cotton, which we now know to be specific for 

 each strain, just as lint length is, with fluctuations, is 

 best effected by weighing the seed-cotton, and then the 

 lint ginned from it. 



From the figure thus obtained, together with the mean 

 seed weight, one can obtain the weight of lint per seed 

 by computation. Determinations by weighings of the 

 seed are unsatisfactory, as a small percentage of seeds are 

 always lost in the act of ginning, though the use of a 

 canvas shoot and a loose overhead cover reduces this loss 

 to about 1 per cent, with the 12-inch gin running as fast as 

 two men can turn it. 



The weighings and computation (by slide-rule) required 

 to obtain the ginning out-turn can be done in about five 

 minutes per sample. If the seed- cotton is weighed out 

 against a fixed weight of 20, 50, or 100 grammes, there is 

 then only one weighing to be done with loose weights, and 

 the out turn can be calculated by mental arithmetic with- 

 out much risk of making a mistake. This reduces the 

 time required considerably, but it still requires three or 

 four minutes per sample. By a simple modification of the 

 steelyard, provisionally patented as the " Slide-Rule 

 Balance," this time was cut down to less than one minute, 

 which is a matter of no little importance when hundreds 

 of samples have to be dealt with. This balance works with 

 two riders and two pans, movement of the primary rider 

 bringing it into equilibrium with the seed-cotton on one 

 pan, and movement of the secondary rider on the unaltered 

 primary bringing the lint into subsequent equilibrium 



