CHEMICAL CHARACTERISTICS OF CORDAGE FIBRES 87 



The chief chemical difference between jute and pure cellu- 

 lose fibres is in the ability of the former to combine directly 

 with basic dyestuffs. In fact, it acts in this respect similarly 

 to cotton which has been mordanted with tannic acid. Jute 

 is also more sensitive to the action of chemicals in general 

 than cotton or linen. On this account it cannot be bleached 

 with much success, as treatment with alkalies and bleaching 

 powder weakens and disintegrates the fibre to a considerable 

 extent. 



The European hemp fibre is not composed entirely of pure 

 cellulose, as it gives a green coloration with aniline sulphate, 

 and iodine and sulphuric acid. It appears to be a mixture of 

 cellulose and bastose. The behaviour of isolated hemp cells 

 with ammoniacal copper oxide solution is quite characteristic. 

 The cell membrane acquires a blue or bluish green colour, and 

 swells up like a blister, showing sharply defined longitudinal 

 striations. The inner cell walls remain undissolved in the form 

 of a spirally wound tube contained inside the strongly swollen 

 mass of the fibre. 



M tiller gives the following analysis of a sample of the best 

 Italian hemp : 



Per cent. 

 Ash ... ... ... ~. ... 0-82 



Water (hydroscopic) Y?r ... 8-88 



Aqueous extract 3-48 



Fat and wax 0-56 



Cellulose ... 7777 



Intercellular matter and 



pectic bodies 9*31 



Manilla hemp is a lignified fibre, and gives a yellow colour 

 with aniline sulphate; iodine and sulphuric acid give a golden 

 yellow to a green colour ; ammoniacal copper oxide causes a 

 blue coloration and a slight swelling. 



The chemical compositions of Manilla, New Zealand, and 

 Sunn hemp respectively are : 



