HA RD WICKE'S SCIENCE- G OSSIP. 



39 



attention of cotton spinners at the present time ; and, 

 indeed, now, one of the vital points with spinners is, 

 who can make the most strong and even yarn out of 

 the same cotton. 



The cotton hair has a most wonderful power of 

 absorption. This is most probably owing to the 

 capillary attraction of the tube of the fibre. We see 

 this property well adapted in lamp wicks, etc. ; but 

 it is often abused. Putting the yarn in a damp 

 cellar, and steaming it in order to increase the 

 weight, is one of the well-known tricks of the trade. 

 It will be readily understood that cotton will absorb 

 a great amount of moisture from our usual atmo- 

 sphere. If we subject cotton that has been in an 

 atmosphere of ordinary temperature to a heat of 

 212°, we should find it would lose about J per cent., 

 through the evaporation of water, which loss would 

 be regained if we replaced the cotton in the former 

 temperature. Any manager of a cotton mill will 

 tell you that cotton will lose weight even to as much 

 as 5 per cent, on the change of from, say, very wet, 

 damp weather to dry or frosty weather. Cotton, to 

 be worked with ease, requires a humid atmosphere. 

 In dry weather, the cotton seems to become less 

 pliable, and so snaps and breaks. When very dry, 

 it also becomes a good conductor of electricity, and 

 is thus attracted to rollers, etc., through which it has 

 to pass. These rollers lick up the cotton, and so 

 make a great amount of waste. 



In continuous dry weather the difficulties of spin- 

 ning are often so serious that the floors of the mills 

 are regularly degged with water to make the atmo- 

 sphere moist. 



In all classes of cotton, more or less, but more 

 especially in the low classes of American and East 

 Indian cotton, when received in Liverpool, there are 

 found small patches of very bright straight fibres. 

 These fibres are very weak and brittle, destitute of 

 twist, and without any tube ; and were formerly 

 thought to be "dead cotton," by which name the 

 fibres were known. With the aid of the microscope, 

 some time ago, it was found that such cotton is 

 really unripe * — cotton which has been gathered 

 before the fibre was mature. Asa consequence of 

 this, little or no cellulose has been deposited, and the 

 fibre is weak. When the vital fluid is withdrawn 

 the cotton hair collapses entirely, and forms a flat, 

 glassy, structureless fibre. Having no tube it cannot 

 be dyed ; being without twist it cannot be formed 

 into thread. Altogether, it is a useless cotton, and 

 not only useless, but very damaging when mixed 

 with other cotton, as it usually is. And yet it is 

 quite abundant in some classes of cotton. Machines 

 have been invented to open unripe pods, and to ex- 

 tract the cotton and seeds : so we cannot expect any 

 reduction in the quantity of this unripe fibre in future. 



* One of these unripe fibres will be seen in the illustration in 

 the January part of this Journal. 



Cotton growers are always in a hurry to realise on 

 their crops, and this is the result. 



When cotton, having a great proportion of unripe 

 or half-ripe fibre mixed with it, is spun into yarn, 

 the short immature fibres, being broken up in the 

 working, form little conglomerations of fibres in the 

 yarn, or what are technically termed " neps." If 

 such yarn, having been woven into cloth, were to be 

 dyed, all these neps would be left untouched by the 

 dye, and the cloth would present a speckled appear- 

 ance, causing great loss to the manufacturer or dyer. 

 From this it will be seen, how very important it is to 

 see that the cotton we buy is free from this unripe 

 fibre ; and here is one of the many cases which point 

 to the usefulness of the microscope in the cotton 

 industry. I am glad to see that the textile industries- 

 are now taking more notice of the teachings of 

 science, and I have not the slightest doubt that the 

 microscope will be found increasingly useful in the 

 future. 



Before concluding, it would be well to compare 

 the cotton fibre with other fibres and hairs of com- 

 merce. I would here refer to Fig. 35, p. 38. Taking 

 from left to right, the first we come to is the regular 

 form of the cotton hair. Next is Lincoln wool, 

 then a common coarse wool. It will be noticed how 

 the rough serrated surface of wool would act when 

 made into yarn. I have previously mentioned that 

 it is owing to the twist in the cotton fibre that we 

 can make thread out of it. In wool the rough 

 serratures act on each other, and enable them to hold 

 together. If we were to try and make thread out of 

 human hair, we should find it difficult, if not im- 

 possible, as human hair has a smooth surface and 

 would not hold together. Remaining on the figure 

 are flax and silk, both of which have a smooth glassy 

 surface, but are of such length that the large number 

 of twists in the yarn is sufficient to overcome the dif- 

 ficulty, and so the flax silk and thread holds together. 



For information respecting the treatment of cotton 

 fibre in manufacture, I would refer the reader to 

 "Cotton-Spinning," by R. Marsden, published by 

 Bell & Son. This volume contains full particulars of 

 the machines through which cotton has to pass in the 

 process of manufacture. 



Transfer of Pictures. — I have been trying to 

 transfer pictures to wood by means of methylated 

 spirit, but have repeatedly failed. I placed the paper 

 on a piece of polished wood, and then soaked the 

 paper with the spirit by means of wadding. After 

 leaving the paper on the board for twenty-four hours, 

 I attempted to rub it off by wetting it, and rubbing it 

 with my finger, and I have never been able to rub it 

 off without tearing the picture. If any reader could 

 inform me how to accomplish this task, either by this 

 or some other method, I should be very thankful. — 

 Josrph Willson. 



