DETECTION OF FRAUDS 



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hand, hence silk making must go on in countries like 

 Japan and China, where wages are low. 



Detection of frauds in clothing. We all know that 

 woolen cloth frequently contains much cotton. We are 

 often sold mercerized cotton, or artificial silk, which is 

 made by chemical means from various vegetable wastes, 

 and it is worth while to know some simple means for 

 detecting these frauds. If one has a microscope, it is 



(a) Cotton. 



(c) Silk. 



very simple to recognize by examination the fiber of silk, 

 cotton, linen, and woolen fabrics. (See illustration.) Some 

 easy tests which can be made at home are the following: 

 If we place silk fibers in hydrochloric acid, they will dis- 

 solve. By boiling wool in caustic soda for five minutes, 

 the wool dissolves. Thus it is very easy to find out 

 whether wool and silk are mixed with other substances 

 in cloth. Linen threads are much stronger than cotton. 

 A very easy way to tell linen from cotton is to place in 

 olive oil for five minutes ; if linen, the material becomes 

 translucent; if cotton, it remains unchanged. 



Experiment. To show the effect of chemical reagents on different fabrics. 

 Materials: Pieces of cotton cloth, wool, and silk of known purity. Test 

 tubes. Beakers. Burner. Hydrochloric acid. Sodium hydroxide. 

 Ammonia. Borax. Washing soda. Nitric acid. Sulphuric acid. 



