tag="{http://www.w3.org/1999/xhtml}a">75

21. Cloth-dyeing Machine 76 22. Dye Beck 77 23. Holliday's Machine for Hawking Cloth 78 24. Continuous Dyeing Machine 79 25. Padding Machine 80 26. Padding Machine 81 27. Dye-tub for Paranitroaniline Red

191 28. Padding Machine for Paranitroaniline Red 192 29. Developing Machine for Paranitroaniline Red 194 30. Indigo Dye-vat for Cloth 199 31. Squeezing Rollers 240 32. Yarn-washing Machine 243 33. Dye-house Washing Machine 244 34. Cloth-washing Machine 245 35. Cloth-washing Machine 247 36. Washing and Soaping Vats 248 37. Steaming Cottage 249 38. Steaming and Ageing Chamber 250 39. Hydro-extractor 251 40. Hydro-extractor 252 41. Automatic Yarn-dryer 253 42. Truck Yarn-dryer 254 43. Drying Cylinders 255 44. Experimental Dye-bath 263

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CHAPTER I.

STRUCTURE AND CHEMISTRY OF THE COTTON FIBRE.

There is scarcely any subject of so much importance to the bleacher, textile colourist or textile manufacturer as the structure and chemistry of the cotton fibre with which he has to deal. By the term chemistry we mean not only the composition of the fibre substance itself, but also the reactions it is capable of undergoing when brought into contact with various chemical substances—acids, alkalies, salts, etc. These reactions have a very important bearing on the operations of bleaching and dyeing of cotton fabrics.

A few words on vegetable textile fibres in general may be of interest. Fibres are met with in connection with plants in three ways.

First, as cuticle or ciliary fibres or hairs; these are of no practical use, being much too short for preparing textile fabrics from, but they play an important part in the physiology of the plant.

Second, as seed hairs; that is fibres that are attached to the seeds of many plants, such, for instance, as the common thistle and dandelion; the cotton fibre belongs to this group of seed hairs, while there are others, kapok, etc., that have been tried from time to time in spinning and weaving, but without much success. These seed hairs vary much in length, from ¼ inch to 1½ inches or even 2 inches; each fibre consists of a single unit. Whether it is serviceable as a textile fibre

depends upon its structure, which differs in different plants, and also upon the quantity available.

The third class of fibre, which is by far the most numerous, consists of those found lying between the bark or outer cuticle and the true woody tissues of the plant. This portion is known as the bast, and hence these fibres are known as "bast fibres". They are noticeable on account of the great length of the fibres, in some cases upwards of 6 feet, which can be obtained; but it should be pointed out that these long fibres are not the unit fibres, but are really bundles of the ultimate fibres aggregated together to form one long fibre, as found in and obtained from the plant. Thus