Cotton is purchased by the mill authorities in the shape of a bale.
The method is to purchase from cotton brokers, samples being furnished to the buyer from which to make selection.
[Illustration: STOREHOUSES]
The commercial value of cotton is determined by its length, fineness, strength, pliability, smoothness, regularity, color, and cleanliness.
As a rule, the cotton that is the longest is also the finest, but by no means the strongest. Thus, Sea Island cotton has the longest staple with the least diameter, and Hinganghat (an Indian cotton) is much inferior to it in both respects. The strength of the latter, however, is 50 per cent greater than the strength of Sea Island cotton. In every other respect Sea Island cotton is in advance over Hinganghat cotton. It is the most valuable, especially for the production of fine yarns.
The most regular cotton is Orleans, in which the length of the staple varies only a small fraction of an inch. In consequence of this there is less loss in working Orleans than is the case with the other cottons, owing to the fact that their fibers vary in length.
=The Leading Growths of Cotton.= In order to purchase the raw material of the cotton manufacture, to arrange the "mixing" or have much to do with the raw material in any other capacity, one should know as much as possible of its characteristics; for ignorance may cause much trouble and no little loss to those who have to spin the cotton. Each crop differs from the previous one to a greater or less degree, as it depends entirely upon the weather. Thus, in a very dry season there is a "droughty crop" which, while it may be (and generally is) clean and well up in class, will be weak, short, and of irregular fiber. In order to obtain the desired length and strength of staple the buyer will have to pay a relatively higher price than in what may be termed a normal season.
[Illustration: FANCY COTTON LOOM]
Again, in a crop that is poor in class, a defect that may have been caused by too much rain in the early or middle stages of its growth, or by unfavorable weather for the production of cotton of good grade, the staple will probably be all that could be desired, leafy and small, but the buyer will have to pay more to obtain his usual grade, especially if he requires it for good filling. Then there are seasons when the crop turns out fairly well in class and staple, but the cotton is wasty, dirty, or abnormally leafy; and in this case the buyer has to exercise great care and judgment in calculating the extra loss that will ensue.
The terms of purchase of cotton include an allowance of 4 per cent for tares. That is, a bale of cotton weighing 400 pounds would be paid for as 384 pounds, or should the buyer have reason to believe that the tares are unusually heavy, he has the option of claiming the actual tare. This is ascertained by stripping ten bales and weighing the covering and the hoops, which means considerable work, and although it is at the option of the buyer, it is an exception rather than the rule.
As a result of these causes we find cotton divided into the following grades:
=Full Grades of Cotton.= Egyptian cotton is graded as follows: extra fine, fine, good, fully good fair, good fair, fair, middling fair, middling.
Indian cotton is graded as follows: superfine, fine, fully good, good, fully good fair, good fair, fully fair.
Brazilian cotton may be classed: fine, good, good fair, fair, middling fair, middling.
American cotton has seven grades: fair, middling fair, good middling, middling, low middling, good ordinary, and ordinary.
In addition to the full grades there are half and quarter grades. The American cottons are graded as follows:
_Full Grades._ _Half Grades._ _Quarter Grades._
Fair, Strict middling fair, Barely fair, Middling fair, Strict good middling, Fully middling fair, Good middling, Strict middling, Barely middling fair, Middling, Strict low middling, Fully good middling, Low middling, Strict good ordinary, Barely good middling, Good ordinary, Strict ordinary. Fully middling, Ordinary. Barely middling, Fully low middling, Barely low middling, Fully good ordinary, Barely good ordinary.
The following are a few of the leading varieties of cotton, with the numbers of yarn they will make:
_Cotton._ _Length._ _Warp._ _Filling._
Sea Island (selected) 1-3/4 to 2-1/4 up to 200 250 to 300 Sea Island (ordinary) 1-3/4 to 2 150 220 Florida Sea Island 1-3/4 to 2 150 220 Georgia 1-1/2 to 1-7/8 120 180 Egyptian 1-1/4 to 1-1/2 70 120 Peeler 1-1/4 to 1-3/8 50 70 Orleans or Gulf 1-1/16 to 1-1/4 40 60 Upland 1 to 1-1/8 30 45 Texas 7/8 to 1-1/16 25 35
During the last few years considerable discussion has taken place among mill men, both in this country and abroad, bearing upon the subject of moisture contained in baled cotton. Of course the natural moisture in the cotton fiber varies, as might be expected, from year to year, according to the character of the season during the picking.
The standard of moisture is based upon what is known as regain, that is, if 100 parts of absolutely dry cotton are exposed to the air, they will absorb about 8-1/2 per cent of moisture, although a much higher per cent is sometimes found.
In some of the small Southern mills located in the cotton raising section, the cotton is delivered by team direct from the gin, without going through the compress. In this way they save the greater part of transportation expense. They also save in the strength of the cotton fiber itself, since the process of compression injures the fiber. They get better cotton, being nearer the source of supply and having better opportunities for selection.
When the cotton arrives in the shape of a bale, it is necessary to cut ties and loosen up the cotton before use. This may be done in two ways. One method being to pull the bale apart by hand, and the other to pass it through a bale breaker or similar machine, which loosens up the cotton by means of beaters. It now starts on a continuous journey through successive machines until it is made into yarn. The yarn is made into a warp, and the warp interlaced with the filling yarn to make cloth, and the cloth finished for the market.
Not every country is adapted for making cotton yarn, for certain conditions are necessary to manufacture good yarn. If the atmosphere is too warm or too dry, the fibers will become brittle and will not twist well; if too wet they collapse and stick. Lancashire County, England, seems to have been fitted by nature for cotton spinning. It has just the right climate, a moist temperature, and copious water supply. There are hills on the east of the valley, forming a water shed, and the town lies in a basin covered with a bed of stiff clay, that holds the water, allowing it to evaporate just fast enough to keep the air in the moist condition needed to fit the fibers for weaving. Countries that have not these conditions are obliged to produce them by artificial means--humidifying, etc.
[Illustration: PICKER ROOM
1. Hopper where the cotton from the bale is fed into Picker.
2. "Lap" showing how the cotton is prepared for the card.
3. Picker Machine (complete).]
CHAPTER X
MANUFACTURE OF COTTON YARN
[Illustration: PICKER ROOM--SHOWING END VIEW OF PICKER
1. Lap of Cotton.]
=Picker Room.= The first step in the conversion of the bale of cotton into yarn consists in giving the cotton fibers a thorough cleaning.
This is accomplished by feeding the cotton to a series of picker machines called in order, bale breaker, cotton opener and automatic feeder, breaker picker, intermediate picker, and finisher picker.
These machines pull to shreds the matted locks and wads of cotton (as we find them in the bale), beat out the dirt, stones, and seeds, and finally leave the cotton in the form of batting upon the cylinders; this batting passes from one machine to another until it issues from the finisher picker as a downy roll or lap.
(Sometimes the bale breaker is not used in the mill.)
[Illustration: CARD ROOM
1. Roving Can--receptacle to hold the sliver. After it is filled it is transferred to either ribbon lap machine or drawing frame.
2. Cylinder of the card. The cotton is on this cylinder in the form of a web.]
=Carding Machine.= When the lap of cotton leaves the picker it goes to the carding machine, where it is combed into parallel fibers by means of a revolving cylinder covered with wire teeth called card clothing.
As the cotton is fed to the card in the form of a sheet or lap from the picker, it is supposed to have been freed from a considerable quantity of sand, seed, etc., but there still remain nep, fine leaf, and short fibers, which are removed during carding.
On leaving the card cylinder the lap has become a gossamer-like web thirty-nine inches broad. This web next passes through small "eyes,"
which condense it into a narrow band about an inch in width, known as card sliver.
When a lap is delivered from the finisher picker, it should weigh a given number of ounces per yard. The method of ascertaining the weight is to make each lap a standard number of yards in length and weigh each lap. The machine can be regulated so as to give the desired weight per yard.
=Combing.= When an extremely fine and strong yarn is required, in addition to carding, the fibers are also subjected to the process of "combing." This may be said to be merely a continuation of the carding process to a more perfect degree. The chief object is to extract all fibers below a certain required length, and cast them aside as "waste." This is done in order to secure the very best fibers calculated to give the strongest and best results in the spun yarn.
The process of combing follows carding. The card delivers the cotton in the form of a sliver or strand, while the combing machine requires the fibers to be delivered to it in the form of sheets, nine to twelve inches wide. This is done by taking a number of card slivers and forming a lap of them by passing the sliver through a sliver lap machine. The laps are passed through the comber. This machine consists essentially of a series of rollers, nippers, and rows of metal teeth.
By the action of these, the short fibers are separated and combed out, and the long ones arranged in parallel order in the form of a thin, silky strand, in which condition it is sent to the drawing frames to be drawn out. Of course it must be understood that a combing machine is used by only a small percentage of cotton spinners. For ordinary purposes a sufficiently good quality can be made without a comber. As there is from 15 to 35 per cent waste to this operation it may be readily seen that it is costly, and limited entirely to the production of the very best and finest yarns, such as those intended for sewing or machine thread, fine hosiery, lace curtains, underwear, imitation silks, and fine grades of white goods. There are combing machines that comb short staple cotton.
=Drawing.= The cans containing the slivers are taken from the card or combing machine (as the case may be) to the drawing frame. The object of this machine is mainly to equalize the slivers, combining a number of them together so as to distribute the fibers uniformly. The condition of the fibers on leaving the card or comb is such that a slight pull will lay them perfectly straight or parallel, and this pull is given by the drawing frame rollers. Of course the fibers coming from the comb are parallel, but it is necessary to alternate them by the drawing. The drawing frame is a machine consisting of a number of sets of rollers, the front roller having a greater speed than the rear ones.
[Illustration: COTTON COMB ROOM
1. The cotton in the form of a "lap" ready to pass through the comb.]
The slivers, which are as nearly as possible the same weight per yard, are combined together in the drawing and emerge from the pair of front rollers as one sliver weighing the same number of grains per yard as a single sliver fed up at the back. This process is repeated two or three times, according to requirements, the material then being referred to as having passed through so many "heads" of drawing. It is not unusual to pass Indian and American cotton through three deliveries.