180 THE DEVELOPMENT OF RAW COTTON 



cover a great part of the results described in the text of 

 this book. Other determinations, such as diameter of the 

 lint hair, weight of a centimetre of the lint hair, thickness 

 of the wall, amount of twist, etc., have been made only 

 on samples chosen as typical of particular sets of cir- 

 cumstances. 



Ginning. The samples were ginned on a 1 2-inch roller 

 gin made by Platt Brothers of Oldham. The author is 

 indebted to this well known firm for the very courteous 

 loan of one of their 4-inch " Missionary " gins to use in 

 England, while awaiting the arrival of a little Churka gin 

 from India, but these two latter implements were only 

 used for a small part of the work here described. 



The 12-inch gin was run at about twenty-five revolutions 

 of the roller per minute by hand, this slow speed being em- 

 ployed in order not to damage the fibre unnecessarily ; in 

 the ordinary way these hand-gins depreciate the quality of 

 fine cotton very noticeably. For small samples the little 

 Churka gin, or its modification with a twist-geared iron 

 upper roller, is extremely useful, being so easily cleaned, 

 and for work of this class it would be worth while for any 

 investigator to make, or have made, a rather larger and 

 improved form of this implement. The ordinary roller 

 gin necessitates some troublesome attention to insure 

 that the ginning out-turn is correctly obtained, since lint 

 coming off the roller is liable to be lost by coiling, round 

 the roller axle. In any case a canvas shoot should be 

 mounted on a light frame which is clipped under the 

 beater-blade frame, in order to catch the seed, which other- 

 wise has to be picked out of the interstices of the machine. 



