Appendix





=Testing Textile Fabrics.= This is an age of adulteration, and next to

food there is probably no commodity that is adulterated as much as the

clothing we wear. Large purchasers of textile fabrics and various

administrative bodies, such as army clothing departments, railway

companies, etc., have adopted definite specifications to ensure having

good material and workmanship. Before the fabrics are accepted they

are examined carefully by certain tests to see if they meet the

requirements. Wholesale and retail merchants insist on various

conditions when purchasing fabrics in order to conform to the

increasing needs of the public. Hence every manufacturer, buyer, or

dealer in fabrics should be familiar with the tests used to determine

the quality of goods he is about to buy.



The tests used are as follows:



1. Identification of the style of weaving.



2. Testing the breaking strength and the elasticity by the dynamometer.



3. Determining the "count" of warp and filling.



4. Determining the shrinkage.



5. Testing the constituents of warp and of filling.



6. Testing the finish and dressing materials.



7. Testing the fastness of the dye.



=Directions for Determining the Style of Weave.= In examining a

fabric for the weave it is first necessary to determine the direction

of the warp and filling threads. This is a very simple matter in a

great many fabrics that have a selvedge--the warp must be parallel to

the selvedge.



In fabrics that have been fulled, raised, and cropped, as buckskin,

flannel, etc., the direction of the nap will indicate the direction of

the warp, since the nap runs in this direction.



In the case of fabrics with doubled and single threads, the doubled

threads are always found in the warp.



In fabrics composed of cotton and woolen threads running in different

directions, the cotton yarn usually forms the warp and the woolen yarn

the filling. Then again the warp threads of all fabrics are more

tightly twisted than the filling threads, and are separated at more

regular intervals.



Sometimes in stiffened or starched goods threads running in only one

direction can be seen. In this case they are the warp threads.



If one set of threads appears stiffer and straighter than the other,

the former may be regarded as warp, while the rough and crooked

threads are the filling. The yarn also gives one a hint, since the

better, longer, and higher number material constitutes the warp, while

the thicker yarn the filling.



The direction of the twist of the thread is conclusive; if one set has

a strong right twist and the other a left twist the first is the warp.



After determining the direction of the warp and filling, the next

point is to determine the interlacing of the warp and filling

threads--the weave. This may be done by inspection or by means of a

pick-glass and needle. The weave may be plotted on design paper

(plotting paper), the projecting warp threads being indicated by

filling up the corresponding square, and leaving those referring to

the filling threads blank. In this way the weaving pattern of the

sample is obtained, and serves as a guide to the weaver in making the

fabric, as well as for the preparation of the pattern cards for the

Jacquard loom.



=Testing the Strength and Elasticity of a Fabric.= The old-fashioned

plan of testing cloth by tearing it by the hand is unreliable, because

tearing frequently requires only a certain skilled knack whereby the

best material can be pulled in two. In this way an experienced man may

tell good from bad cloth, but he cannot determine slight differences

in quality, because he has exerted his strength so often that his

capacity to distinguish the actual force has disappeared.



The best means of determining the strength of a fabric is by means of

a mechanical dynamometer,[19] which expresses the tensile strength of

the fabric in terms of weight. The machine is very useful to the

manufacturer because it enables him to compare accurately his various

products with those of his competitors. The value of these tests is

sufficiently proved by the fact that all army clothing departments,

etc., require their supplies of cloth, etc., to pass a definite test

for strength.



Breaking tests also afford the most certain proof to bleachers of

cotton and linen goods as to whether the bleaching has burned or

weakened the goods. The same test will quickly determine whether a

fabric has been improperly treated in the laundry.



=Determining the Count of Warp and Filling Threads.= Every fabric must

contain a certain count of warp and filling threads--a definite number

within a certain space for each strength of yarn employed. A fabric is

not up to the standard of density when less than the requisite number

of warp or filling threads per inch is found. For example, if a buyer

was told that a fabric is 80 square, that is, eighty warp threads and

eighty filling threads to the inch, and on examination found only 72

square, he would immediately reject the goods.



The count of warp and filling is determined by means of a

pick-glass--a small mounted magnifying glass--the base of which

contains an opening of one-half inch by one quarter inch, or one

quarter inch by one quarter inch. If the pick-glass is placed on the

fabric the number of warp and filling threads may be counted, and the

result multiplied by either two or four, so as to give the number of

threads to the inch. For example, if I count twenty picks and twenty

threads on a one quarter-inch edge, there are eighty picks and eighty

threads to the inch. A more accurate result can be obtained by using a

pick-glass with a one-inch opening.



=Determination of Shrinkage.= A very important factor in the value of

a fabric is the shrinkage. The extent of this may be determined by

pouring hot water over a sample of about twelve by twenty inches, and

leaving the fabric immersed over night, then drying it at a moderate

temperature without stretching. The difference in length gives the

shrinkage, which is usually expressed in percentage.



=Determination of Weight.= Buyers and sellers of dry goods, when

traveling, are anxious to determine the weight of fabrics they

examine. This may be done by means of small pocket balances so

constructed as to give the number of ounces to the yard of a fabric.



=Testing the Constituents of the Warp and Filling.= Take a sample

piece of the cloth to be examined--the piece must be large enough to

contain specimens of all the different kinds of yarn present in the

material--and separate all the filling and warp threads. Be sure that

all double threads are untwisted.



=Combustion Test; Test for Vegetable and Animal Fibers.= Burn

separately a sample of the untwisted warp and filling threads. If one

or both burn quickly without a greasy odor, they are vegetable fibers,

cotton or linen. If one or both burn slowly and give off a greasy

odor, they are animal fibers, wool or silk. This test is not

conclusive, and further chemical examination--acid test--must be made

to ascertain whether wool is pure or mixed with cotton.



=Acid Test.= The vegetable fibers, cotton and linen, are distinguished

from those of animal origin by their behavior in the presence of

acids and alkalies. The vegetable are insoluble when boiled with a 4

per cent sodium hydrate solution, but readily clear or carbonize when

saturated with a 3 per cent sulphuric acid solution and allowed to dry

at a high temperature in a hot closet. Wool on the other hand is not

affected by the action of weak sulphuric acid.



=Cotton Distinguished from Linen.= If the fibers are vegetable, cotton

may be distinguished from linen by staining the fibers with fuchsine.

If the fibers turn red, and this coloration disappears on the addition

of ammonia, they are cotton, if the red color remains the fibers are

linen. Whenever cotton yarn is used to adulterate other fabrics, it

wears shabby and loses its brightness. When it is used to adulterate

linen, it becomes fuzzy through wear. One may detect it in linen by

rolling the goods between thumb and finger. Linen is a heavier fabric,

and wrinkles much more readily than cotton. It wears better, and has

an exquisite freshness that is not noticed in cotton fabrics.



=Silk Distinguished from Wool.= Place the fabric or threads containing

animal fibers in cold, concentrated hydrochloric acid. If silk is

present it will dissolve, while wool merely swells.



=Artificial Silk from Silk.= On account of the low value of the

artificial and the high value of genuine silk, there is a tendency to

offer the artificial instead of the pure article. Test: When

artificial silk is boiled in 4 per cent potassium hydrate solution it

produces a yellow solution, while pure silk gives a colorless

solution.



A common test is to put the artificial silk in water, where it will

pull apart as though rotten; or to take out one strand of the silk,

hold it between the finger and thumb of each hand and wet the middle

of the strand with the tongue, when it will pull apart as though

rotten.



Artificial silk is inferior in strength and elasticity to pure silk.

Then again it is lacking in the crackling feeling noticed in handling

the genuine article.



=Test for Shoddy.= It is no easy matter to detect shoddy in woolen

fabrics; the color of the shoddy threads is the best evidence. Many

parcels of rags are of one single color, but for the most part they

are made of various colored wools; therefore, if on examination of a

fabric with a magnifying glass a yarn of any particular color is found

to contain a number of individual fibers of glaring colors, the

presence of shoddy can be assumed with certainty.



Woolen goods containing cotton are seldom made from natural wool.

Shoddy yarns, especially in winter goods, are found in the

under-filling at the reverse side of the cloth, as thick, tightly

twisted yarns, curlier than those from the pure wool.



=Determination of the Dressing.= During the various operations of

washing, bleaching, etc., the goods lose in weight, and to make up

this deficit a moderate amount of dressing or loading is employed.

Dressing is not regarded as an adulteration, but as an embellishment.



Various dressing materials are used, such as starch, flour, mineral

matters, to give the goods stiffness and feel on one hand, and on the

other to conceal defects in the cloth, and to give a solid appearance

to goods of open texture. The mineral substances used serve chiefly

for filling and weighting, and necessitate the employment of a certain

quantity of starch, etc. In order that the latter may not render the

cloth too stiff and hard, further additions of some emollient, such as

glycerine, oils, etc., are necessary.



When a fabric filled in this manner is placed in water and rubbed

between the hands, the dressing is removed, and the quantity employed

can be easily determined.



By holding fabrics before the light dressing will be recognized, and

such goods, if rubbed between the fingers, will lose their stiffness.

Loading is revealed by the production of dust on rubbing, and by the

aid of the magnifying glass it can be easily ascertained whether the

covering or dressing is merely superficial or penetrates into the

substance of the fabric.



=The tests of permanence of dyes on fabrics are as follows:=



=Washing Fastness.= Fabrics should stand mechanical friction as well

as the action of soap liquor and the temperature of the washing

operation. In order to test the fabric for fastness a piece should be

placed in a soap solution similar to that used in the ordinary

household, and heated to 131 degrees F. The treatment should be

repeated several times. If the color fails to run it is fast to

washing.



=Fastness Under Friction.= Stockings, hosiery yarns, corset stuffs,

and all fabrics intended to be worn next to the skin must be

permanent under friction, and must not rub off, stain, or run, that

is, the dyed materials must not give off their color when worn next to

the human epidermis (skin), or in close contact with colored articles

of clothing, as in the case of underwear.



The simplest test is to rub the fabric or yarn on white unstarched

cotton fabric. In comparing the fastness of two fabrics it is

necessary to have the rubbing equal in all cases.



=Resistance to Perspiration.= With fabrics coming in contact with the

human skin it is necessary in addition to fastness under friction that

they should withstand the excretions of the body. The acids of

perspiration (acetic, formic, and butyric) often become so

concentrated that they act on the fiber of the fabric.



In order to test the fabric for resistance, place the sample in a bath

of 30 per cent dilute acetic acid (one teaspoonful to a quart of

water) warmed to the temperature of the body, 98.6 degrees F. The

sample should be dipped a number of times, and then dried without

rinsing between parchment paper.



=Fastness against Rain.= Silk and woolen materials for umbrella

making, raincoats, etc., are expected to be rainproof. These fabrics

are tested by plaiting with undyed yarns and left to stand all night

in cold water.



=Resistance to Street Mud and Dust.= Ladies' dress goods are expected

to withstand the action of mud and dust. In order to test a fabric for

this resistance the sample should be moistened with lime and water

(10 per cent solution), dried, and brushed. Or sprinkle with a 10 per

cent solution of soda, drying, brushing, and noting any changes in

color.



=Fastness to Weather, Light, and Air.= Various people have attempted

to set up standard degrees of fastness--for every shade of color is

affected by the action of sun, light, and air--and as a result fabrics

that remain without appreciable alteration for a month of exposure to

direct summer sunlight are classified as "fast," and those undergoing

slight appreciable change under the same conditions as "fairly fast."

"Moderately fast" colors are those altering considerably in fourteen

days; and those more or less completely faded in the same time

(fourteen days) are designated as "fleeting."



=Directions for testing fastness of Color in Sunlight.= Cover one end

of the sample of cloth with a piece of cardboard. Expose the fabric to

the sunlight for a number of days and examine the cloth each day in

the dark and notice whether the part exposed has changed in color when

compared with the part covered. Count the number of days it has taken

the sunlight to change the color.



Brown in woolen materials is likely to fade. Brown holds

its color in all gingham materials.



Dark blue is an excellent color for woolens and

ginghams. Light blues on the other hand usually change.



Black, gray, and black with white. These colors are very

satisfactory for woolen materials.



Black is not a color which wears very well with cotton

fabrics, as it shows the starch (sizing) and often

fades.



Red is an excellent color for all woolen materials. It

looks attractive and wears well.



Red is a very poor color for cotton. It loses its

brilliancy and frequent washing spoils it.



A deep pink is an excellent color for all ginghams for

it fades evenly and leaves a pretty shade.



Green is a poor color for both cotton and woolen

materials unless it is high priced.



Lavender fades more than any other color in textiles.





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