68 USEFUL FIBER PLANTS OF THE WORLD. 



which an even quantity of air circulates, heing constantly reheated at the entrance 

 of the machine (to dry the threads) and cooled again at the exit (to collect the vapor). 

 The skeins arc formed like those from the silk cocoons. {Count de Chardonnet.) 



Starting with paper pulp, which is pure cellulose, this is nitrated, as has heen 

 shown, transforming it into pyroxyline or gun cotton. It is this collodion that is 

 spun, and the "silk" is naturally inflammable to a high degree, and consequently in 

 this form would be a decidedly undesirable form of fabric to use for any purpose. 

 It is necessary to denitrify the silk, therefore, before the processes of spinning and 

 subsequent manufacture. The various pyroxylines reduced in tepid baths lose their 

 nitric acid. Pure water is also effective, though the reaction is even more complete 

 in diluted nitric acid. The nitric acid of the cellulose is removed by a dissolution 

 which takes place more or less quickly in proportion as the bath is warm and con- 

 centrated; but it can be pushed further in proportion as the bath is cooler and more 

 diluted. The elasticity of the artificial silk is claimed to be equal to the natural 

 silk of animal origin. The elongation before rupture is from 15 to 25 per cent. "The 

 real elasticity is about 4 to 5 per cent." A square millimeter of artificial silk will 

 stand a breaking strain of 25 to 35 kilograms. Raw silk will break at 30 to 45 kilo- 

 grams. In density, artificial silk rates at about 1.49, coming between that of natural 

 raw silk at 1.66 and natural boiled silk at (about) 1.43. In luster and brilliancy it 

 is said to surpass the natural article. Examined under the microscope in section, 

 the filament of artificial silk has the appearance of a grooved cylinder. It is claimed 

 that this silk can be produced for 15 to 20 francs per kilogram, or about $1.40 to $1.80 

 per pound, natural silk costing from three to four times as much. The Textile World, 

 Boston Mass., for June 1897, publishes recent interesting statements on this subject. 



Artocarpus incisa. Breadfruit Tree. 



Exogen. Moracew. 



This species is the well-known breadfruit tree of the South Sea Islands. A caout- 

 chouc is derived from the tree which is used as a glue and for calking the canoes of 

 the islanders. Known in Peru as the Arbol del Pan, which means breadfruit tree. 

 The species of this genus are found in India and the East Indies, New Guinea, Poly- 

 nesia, New Zealand, and the Pacific islands. 



Fiber. — "The bark yields a fiber used by the Indians of Loreto for making cloth- 

 ing" (A. Dorca). "The bark of the young branches is utilized for clothing in the 

 more southern islands of Malaysia" (Savorgnan). A. integrifolia, the jackfruit tree, 

 yields a fiber, samples of which were sent to the Paris Exposition from India. The 

 timber is much used for making furniture and resembles mahogany. A. lakoocha 

 also yields a fiber, said to be employed for cordage. 



Arum spp. 



A genus of Aracew, the species of which are found in many parts of the world. 



Fiber. — 1 have never seen the fiber of any species, but Bernardiu states that fiber 

 has been extracted from A. macrorrhizon (now Alocasia macrorrhiza) and from A. 

 funiculaceum (species not in the Index Kewensis). Both are included in the Flax 

 and Hemp Commission list, the first- named fiber measuring 19 feet, and the second, 

 " aerial root, 10^ to 14| feet; petiole, 2 feet 6 inches." 



Arundinaria falcata. Himalayan Bamboo. 



Endogen. Graminece. Cane-like grass, 6 to 10 feet. 

 Western Himalayas, above 4,000 feet elevation, but descending to the plains in the 

 eastern. "The leaves are used for roofing and baskets" (Watt). The Kew Mas. 

 exhibits a rough mat made from the split stems in India. See also Jiambttsa and 

 Dendrocalamus for other forms of bamboos. The Harvard University botanical col- 

 lection contains some examples of Japanese fans from A. japonica. 



