M. TECHNOLOGY. 543 



the United States, as furnishing an important fibre, possess- 

 ing numerous points of superiority over the common hemp, 

 especially in view of the fact that it accommodates itself 

 to more barren regions and requires no culture. Being her- 

 maphrodite, and not dioecious, it produces on a given area a 

 greater number of plants, and therefore the amount of tex- 

 tile fibre is much greater. It begins to grow toward the 

 end of April, and flowers in July. It succeeds especially 

 well in dry seasons. The height of its stalks is about five 

 feet, and its pulp furnishes a most excellent material for pa- 

 per. 1 F, October 15, 1874, 164. 



PREPARATION OF WOOD-PASTE FOR PLATES, ETC. 



The mass obtained by the following process, though brittle 

 at first, acquires a surprising degree of firmness after gradual 

 drying in the air, and the separate particles of wood may be 

 firmly united and hardened by moistening three or four 

 times, as soon as it is firm enough, with about a 5 per cent.* 

 solution of potash, and then drying it thoroughly. By sub- 

 stituting bichromate of potash for the potash, it may also be 

 rendered water-proof as well as hard, and by adding different 

 dye-stuffs, or the crude dye-woods, to the alum mordant, col- 

 ored wooden plates and objects may be produced. One 

 hundred parts of sawdust (best of soft wood) are boiled for 

 half an hour in a concentrated solution of 100 parts of sul- 

 phate of alumina, in water, and then allowed to cool. Fifty 

 parts of glue, dissolved in 100 parts of boiling water, are 

 then intimately mixed with the above mass, and the whole 

 thoroughly kneaded and subjected to a very high pressure. 

 34 C, XX., 1874, 159. 



PREPARATION OF EBONITE. 



The use of ebonite, one of the newer preparations of India 

 rubber, is constantly increasing, on account of its better ap- 

 plicability to many purposes in the arts than its near ally, 

 vulcanite. The two substances are quite similar, being com- 

 posed of India rubber and sulphur, with some preparation of 

 gutta-percha, shellac, asphalt, graphite, etc. ; although these 

 latter are not essential. In vulcanite, the amount of sulphur 

 does not exceed 20 to 30 per cent., whereas in ebonite the 

 percentage of sulphur may reach as high as 60. An in- 



