COTTON SAMPLING. 101 



shown by the fibres as they are being pulled asunder is carefully noted, 

 and this property and behaviour are known as the staple. Cotton 

 brokers and buyers have by long practice become experts in the dis- 

 crimination, the pulling, and valuing of cotton staples. When several 

 staples have been pulled, they are laid on the coat sleeve of the left arm 

 and compared. If they show an approximate uniformity of length, each 

 is regarded as a good and reliable staple. 



To ascertain the strength of a number of fibres collectively, a staple 

 that has already been drawn as to length is held tightly between the finger 

 and thumb of each hand, and then a sudden jerk is made and a judgment 

 formed as to the strength of the staple. The whole of the sample from 

 which the fibres have been taken is next lifted up to see what amount of 

 soil or sand will drop from the cotton, on the brown paper of the parcel. 

 This decides the amount of dead-weight impurities that the sample 

 contains, and influences the price offered by the buyer. 



The amount of leaf present in the cotton, so long as it is not too large, 

 is not of itself so detrimental, but is regarded by the cotton buyer as a 

 good sign, showing that the cotton has not been very roughly treated in 

 the ginning process. If the leaf in the sample is very broad, it is surmised 

 that there will be some difficulty experienced in scutching and cleaning 

 the cotton in the various processes through which it has to pass before 

 it is made into a yarn. 



Neps is a term used when a number of fibres have become rolled 

 together and entangled into a dense white opaque speck in the cotton 

 web from a carding engine. They are often shown up prominently and are 

 indicative of an irregular yarn. 



To the naked eye they always seem to be only specks of white 

 cotton distributed in the gossamer carded web of fibres, brought from the 

 main cylinder by the doffer. To understand the construction of neps 

 thoroughly, it is a good plan to place one or two under the low-power of 

 a microscope. When a nep is on the field of the stage, it is seen to be 

 composed of fibres that are entangled together in the centre very tightly. 

 It is this tightly entangled centre that prevents the fibres from un- 

 ravelling and these form the white opaque nep. 



The exterior fibres of a nep are loosely disposed, and readily attach 

 themselves to slivers that are being drawn or twisted. 



Fig. 68 is a photo-micrograph sketch of two dense opaque neps as 

 seen under the microscope, showing the fibres entangled with abrupt 

 ends. The presence of neps in the yarn reduces its value com- 

 mercially. In fabrics newly woven, which have to be dyed, it implies 

 that the spinning processes have been defective. When the neps appear 

 in raw cotton, it is often a result of defective ginning. 



