Timbers. 



96 



[Feb. 1907. 



was performed ; and this plan also failed, because the fibres were cut off iu lines 

 diagonal to their own length, and were consequently too short to make good pulp. 

 There were other difficulties attending the process not necessary here to mention. 

 Such was the state of the art prior to Voelter's invention ; and his improvement 

 in the art consists in grinding or milling away in detail from the bundles of 

 fibres which make up a piece of wood by acting upon them by a grinding surface 

 which moves substantially across the fibres and in the same plane with them. 

 In carrying out this improvement upon the art Voelter splits a log of wood and 

 applies the flat side upon the stone, and then the stone so revolves as to cause 

 points upon its surface to pass the fibres in lines perpendicular, or nearly so, to 

 the length of the fibre, By this mode of proocedure it is possible to obtain a 

 sufficiently long fibre and save much power. Voelter's improvement in the art 

 consists, further, in re-grinding the fibres by causing them, after being separated 

 from the block, to pass under other blocks of wood, which are being reduced to pulp, 

 upon the same stone. The fibres torn out at the first operation are thus rolled over 

 and crushed again and separated into smaller fibre. 



Voelter's improvement in the machinery are in an arrangenent of pockets, 

 with reference to the grinding; surface, so as to hold the blocks of wood in such a 

 position that their fibres may be separated from the blocks in the manner described, 

 and whereby fibres may be reground, and in a contrivance for feeding up the blocks 

 by a positive feed instead of by force derived from weights or springs, as formerly 

 practised ; and a contrivance for causing the feed to cease automatically. 



BACHET-MACHARD PROCESS OP DISINTEGRATING WOOD. 



Messrs. Iwan Koechlin & Co. have carried on the Bachet-Machard Patent at 

 the Isle Saint Martin, near Chatel (Vosges), France, and it has also been experimented 

 with on a large scale at Bex and at Sb. Typhon, Switzerland. At the start the in- 

 ventors had in view the saccharification of wood, the paper pulp being intended to 

 be only a secondary product of the manufacture of alcohol ; but in practise the 

 inverse result has been obtained, the paper pulp becoming the principal product, and 

 alcohol the secondary one. 



The wood, previously sawn in thin discs, was thrown into tubs, the filling of 

 which was then completed with water and sulphuric acid, the latter in the proportion 

 one-tenth- Each tub would contain 188 cubic feet ; eighteen hours boiling was 

 needed : the discs were then washed as well as possible in order to eliminate the acid, 

 then passed through the crushers and the mills. Bach 31 1'3 cubic feet produced about 

 3301bs. of dry pulp ; 65 lbs. of acid and 136 lbs. of coal were used for the production of 

 220 lbs. of pulp. Calculating the value of the wood at 38 cent per cubic foot, the 

 cost of production of 220 lbs, of pulp would be 8s. 



With the Bachet-Machard method a brown pulp is obtained producing a good 

 brown folding paper costing about 3s. 6d. per 100 lbs. dry pulp. This brown is easily 

 transformed by a half bleaching into a blond pulp costing about 8s. 4d. per lOO^lbs., 

 and this can be utilised with or without mixing, for the manufacture of wrapping 

 paper and of all the coloured papers. Up to the present time a method for econo- 

 mically transforming this into white pulp had not been found (1. " Dictionnaire de 

 Chimie," Wurtz, tome II., p- 749, et seq.) 



The inventors think that the tenth of acid, which they cause to react at 212F 

 Upon the wood, saccharifies the ligneous, or rather the incrustating substance with* 

 out touching the cellulose fibres ; thus the cellulose becomes easily separated into 

 fibres by mechanical means. It is probable that the acids modify the incrustating 

 substance and render it friable, and at the same time certain principles of the wood 

 are converted iuto glucose. The process is the same as with straw and esparto, 



