BLAVATSKY 



766 



BLEACHING 



them. This caused them to crack, when they 

 could be moved or further broken by the tools 

 at his command. In ordinary blasting oper- 

 ations, such as occur in railroad construction 

 and mining, holes are bored to the requisite 

 depth by means of drills, the explosive is intro- 

 duced, the hole is tamped or filled up with 

 broken stone, clay or sand, and the charge is 

 exploded by means of a fuse or by electricity. 

 In larger operations, mines or shafts of consid- 

 erable diameter take the place of the holes 

 above described. 



In the construction of the Panama Canal 

 blasting was resorted to on a scale which sur- 

 passed all previous operations. The largest 

 single blast was used at the blowing up of 

 the Gamboa dyke at the northern end of the 

 Culebra (now Gaillard) Cut. Here forty tons 

 of dynamite were used, placed in 1,000 holes 

 each containing about eighty pounds of the 

 explosive. When all was ready for blasting, 

 on October 10, 1913, President Wilson, in Wash- 

 ington, touched an electric button which com- 

 pleted a circuit with the explosive, more than 

 2,000 miles distant. Instantly a huge explosion 

 took place, tearing down the dyke and removing 

 the last obstacle to the joining of the waters 

 of the east and west. 



BLAVATSKY, bla vahts ' ke, HELENA PE- 

 TROVNA HAHN-HAHN (1831-1891), a famous 

 Russian spiritual leader whose teachings em- 

 body the doctrines held by modern theosophists 

 (see THEOSOPHY). During twenty years of 

 travel in various parts of the world she made a 

 special study of the mystic factor in religion, 

 and in 1858 became a famous spiritualistic 

 medium in Russia. Later she moved to the 

 United States, where in 1875 she founded the 

 Theosophical Society. Four years afterward a 

 branch society was organized in Bombay, India. 

 Though her claims as a worker of miracles were 

 disproved, she is regarded by theosophists as 

 their greatest leader, and when she died she 

 had nearly 100,000 followers in England, 

 France, the United States and Canada. Her 

 most important work, Isis Unveiled, is the text- 

 book of the theosophists. 



BLEACHING, bleech ' ing, from the German 

 bleichen, meaning to whiten, is the process of 

 making cotton, linen, wool, silk and other fab- 

 rics white by removing from them their natural 

 coloring matters. Bleaching is practiced in its 

 simplest form by the housewife who spreads 

 her washing on the grass to whiten in the 

 sunlight, a custom that originated many cen- 

 turies ago. The process of bleaching is sup- 



posed to have been known to the Egyptians, 

 Babylonians and Hebrews. The ancient 

 method, which was in use until the eighteenth 

 century, consisted in spreading the cloth on a 

 stretch of grass, and leaving it exposed to the 

 air and sunlight for several months, with 

 sprinklings of water each day. 



In the eighteenth century the Dutch discov- 

 ered a new method, and Holland became a 

 very important center of the bleaching indus- 

 try. The fabrics were steeped repeatedly in 

 potash lye, soaked in buttermilk for about a 

 week and then washed and spread on the 

 ground to whiten. The Hollanders obtained 

 such good results that the name Hollands, 

 still in use, was given the excellent fabrics 

 bleached in this manner; also, a very desirable 

 quality of linen, which was spread on plots of 

 grass, came to be known as lawn. The Scotch 

 and Irish still bleach their fabrics by spreading 

 them on the grass, a process called crofting, 

 from the Scotch word croft, meaning a small 

 tract of meadow land. 



Bleaching as carried on at the present time 

 is a complicated process requiring the special 

 machinery of the modern factory. It consists 

 of steepings, boilings, washings and dryings 

 and the use of various chemicals, particularly 

 the bleaching powder called chloride of lime. 

 The operations vary according to the materials 

 of which the fabric is composed, and according 

 to- the fineness or coarseness of the yarn. Cot- 

 ton bleaches more quickly than linen and re- 

 quires fewer operations, for the latter must 

 be subjected first to a series of alkaline boil- 

 ings to dissolve the impurities that are present 

 in the flax fiber. Linen fabrics are often 

 exposed to the action of air, light and moisture 

 for several days, as this is supposed to make 

 the fiber retain its strength, and it adds to the 

 life of the cloth. This step of the process is 

 called grassing. 



Wool and silk goods in the process of bleach- 

 ing are subjected to the fumes of burning 

 sulphur; the sulphur combines with the color- 

 ing matters in these fabrics to form a colorless 

 compound without destroying the coloring mat- 

 ters. Washing bleached silk or wool goods sev- 

 eral times with soap containing potash makes 

 them turn yellowish, for the soap destroys the 

 colorless compound. Hydrogen peroxide is 

 coming into general use as a bleaching agent 

 for silk. 



Straw, beeswax, feathers, hair, ivory, oils, 

 sponges and the rags and paper used in paper 

 making are also bleached. B.M.W. 



