60 BRAZILIAN COTTON 



written me the following letter which will be specially instructive to 

 those who intend to establish roller ginning factories in the Northern 

 parts of Brazil : — 



" As we understand the bulk of the cotton gro\\'n in North- 

 eastern Brazil is of the clean or Black Seed variety, we have com- 

 pared the production of a 50-saw gin with that of a roller gin of 

 the single-action type, each machine being fitted with automatic 

 feeders. We have further assumed that each machine forms a 

 unit in a scheme for automatically conveying the ginned cotton 

 to the baling room. 



" One single-action (single roller) gin, 40in. wide, should 

 average throughout the day 1301b. lint per hour. 



" One 50-saw gin with 12in. saws should average throughout 

 the day 4501b. lint per hour, or a production rate ratio of 3-4 to 1. 



" If a woolly seed cotton is being ginned this ratio would 

 probably rise to say 5 to 1 owing to the more positive action of 

 the saws in detaching the fibre from the seed. 



" In the latter case we have made our comparison with a 

 40in. double-action (single roller) gin as being a more suitable 

 machine for ginning woolly seed varieties. 



" We should expect the production to be about 701b. per 

 hour for the roller gin as against approximately 3501b. per hour 

 for the saw gin. The relative advantages of the two types of 

 machines depends entirely on the line of view taken. From a 

 production standpoint the saw gin is of course well in front of the 

 roller gin : the question ginners have to decide is whether it will 

 pay to sacrifice output for quality. 



" In a district or tract of country where the weight of woolly 

 seed cotton grown is very great and the fibre of only moderate 

 length as in Southern Brazil (Sao Paulo), the number of roller 

 gins would have to be so large, together with the increased cost 

 of installation, upkeep and labour that preference would be given 

 in those parts to the saw gin. 



"As regards long stapled cottons (we refer to the black 

 seed varieties) no one in their senses ivould ever dream of ginning- 

 these on a saw gin as the result would he absolutely ruinous both to the 

 even length of the fibre as well as its general appearance : the very 

 fact of these fine cottons being torn from their seed and then 

 dragged through the grate bars in the roll box cannot other- 

 wise but seriously damage it. 



" The roller gin treats these cottons in a far different manner, 

 the action of the roller gently detaches the fibre from its seed 

 and retains to its fullest extent the length of the staple ; the 

 action of the roller also assists very materially in giving to the 

 cotton that silky appearance which is such a feature in all better- 

 class cottons. To enable you to make a comparison between 

 the cost of the different types of machines, we have pleasure in 

 giving herewith the respective prices of these machines, viz : — 



