166 BLEACHING, BLUEING, STARCHING 



Hot-water starch is made by moistening starch with cold 

 water and then slowly stirring into it sufficient boiling water to 

 make a transparent paste. Under the influence of heat and 

 moisture the little sacs which hold the starch burst and set the 

 starch free. The starch which is set free mingles with the 

 water and forms a clear transparent paste which hardens to a 

 jelly on cooling. When this starchy substance is put on 

 material, it causes the fibers to cling firmly together and 

 stiffens the clothes. Collars, cuffs, shirts, and materials which 

 need to be very stiff should be dipped in raw starch; laces, 

 curtains, and dresses which require less stiffening should be 

 dipped in hot-water starch. A strong glaze can be secured 

 by adding a pinch of borax to cold starch, and a pinch of 

 borax or a lump of paraffin to hot starch. 



The strength of raw starch and the thickness of the starch 

 paste vary with the materials to be starched. For fine 

 materials a thin starch is best, because a thick starch would 

 stiffen them to the tearing point. For thick, closely woven 

 materials a thin starch is also needed, because the heavy and 

 numerous fibers would absorb too much thick starch and 

 become too stiff. But, for coarse and loosely woven materials 

 a thick starch is necessary, because the loose threads absorb 

 little water and secure little starch. 



Sources of starch. Laundry starch is obtained mainly from 

 corn and potatoes, although some is made from damaged wheat, 

 and a small amount of the highest grade is made from rice. 

 Starch is composed of microscopic granules, which vary greatly 

 in shape and size in different plants ; those of the potato are 

 shell-shaped and nearly twice as large as the round, lens-shaped 

 granules of wheat starch ; rice granules are less than one tenth 

 the size of potato granules; the granules of corn are smaller 

 than those of wheat, but laiger than those of rice. The stiffen- 

 ing power of starch depends largely upon the size of the granules, 



