Agricultural and Technical. 



195 



these various processes differ very much, both in their principles 

 and in their mode of separating the fibre from the other portions 

 of the plant. They may, however, be all classed under two 

 heads, — the mechanical, in which the operations are conducted in 

 a dry state ; and the chemical, in which moisture is more or less 

 necessary. In the first the object is obtained by the various 

 parts being mechanically separated from each other ; in the latter 

 the plant itself is disintegrated, either by the action of fermenta- 

 tion, which destroys, or of some solvent, which abstracts, the 

 cementing matter hy which its parts are held together. Of the 

 first but little need be said, as, except for rough goods not re- 

 quiring to be bleached, as canvass, rick covers, rope-yarn, &c., 

 it could not at present be advantageously used ; however, as it 

 costs as much to steep bad straw as good, and the expenses in 

 some such cases exceed the value of the produce, it would appear 

 that the dry or mechanical process may be most beneficially tried 

 when the raw material is of inferior quality, — where there is a 

 difficulty in steeping it properly, — or where coarse fibre only is 

 required. Several modes have, from time to time, been devised 

 for effecting this mechanical separation, of which the following 

 are those most entitled to notice. 



In 1812 Lee took out a patent for this purpose, to which Par- 

 liament accorded a peculiar privilege, that the time for specifica- 

 tion should be extended from 6 months to 7 years. This was 

 shortly taken up by the Irish Linen Board, who expended 6000/. 

 in their endeavours to introduce it in the flax districts : one of 

 the machines is still preserved in the White Linen Hall at 

 Belfast. Before the time for specification arrived another patent 

 was taken out by Hill and Bundy, in 1817, and more recently 

 those by Donlan and others have been brought before the public. 

 On the Continent the same attempt has been made, and with like 

 success. Some few years back M. Christian, ancien Directeur 

 du Conservatoire des Arts et Metiers, devised a mechanical pro- 

 cess for the separation of the fibre, which appeared to answer 

 well at first, but was afterwards gradually abandoned. 



Even in the event of a successful result in the separation, the 

 goods manufactured from the fibre are always liable to be injured 

 by moisture, or any other condition that would act upon the 

 azotized substance, which would still remain enveloping and 

 cementing the fibres- together. 



The second, the chemical or icet process, must be considered 

 under three different heads : — the first, when the separation is 

 effected by simple fermentation, known as steeping the second, 

 where it is due to the abstraction of the azotized extractive com- 

 pound, by the agency of chemical solvents ; the third, where simply 

 loater, either heated or in the shape of steam, is used. In the 



