TO THE MANUFACTURE OP PAPER. 65 



diminish the theoretical proportions. Thus, at the mills of Gueures 

 and of Valernier, in operating in open boilers, at a temperature of 100 

 deg., a ley of double the theoretic quantity left the plant badly dis- 

 integrated, after twenty-four hours boiling. At Mont Saint Guibert, 

 where rotary boilers are used, at a temperature of 140 and under a hand- 

 pressure of four atmospheres, the plant was burnt and all its cohesion 

 destroyed, in leys containing merely the theoretic quantity and even 

 less, and after twenty, twelve, six hours of boiling. It therefore requires 

 a very careful study, according to the apparatus, to retain in the alfa all 

 its value as regards condition and solidity. Is the plant more or less 

 green ? Is the pressure more or less high 1 Here are two considera- 

 tions which will necessarily vary the quantity of caustic and the 

 time of boiling. Again, are the operations carried on without pres- 

 sure in coppers where the ley is unagitated? Or are they car- 

 ried on with apparatus where the ley alternately rises and falls through 

 the mass ? Further, there are modifications in the quantities of chemi- 

 cals to be used which practice alone can teach, but which are essential to 

 be known. 



We have hitherto supposed that the alfa simply cut i nto four or five 

 parts is operated upon : this gives a good result ; but I ought to mention 

 a very ingenious machine, which its inventor, M. Edmund Bertin, set 

 at work for our experiments. In M. Bertin's machine, the alfa is placed 

 lengthwise under a roller, which in rotating, draws it systematically 

 between cylinders, where the stalk is crushed, firstly from end to end, 

 without being torn. 



From these cylinders, the alfa passes between hinged tables, in which 

 are combined two movements — the first movement causes the plant to 

 advance lengthwise under the cylinders; the second movement, 

 perpendicular to the other, twists the alfa leaf as it advances, and de- 

 posits it in grooved receptacles, still without tearing it. The alfa thus 

 bruised lengthwise and crosswise, is a mass of loose filament, admirably 

 prepared for boiling and washing, without requiring pressure and large 

 quantities of caustic agents. 



I believe that M. Bertin's machine will be generally used in esta- 

 blishments for the preparation of textile plants. It economises the cost 

 of re-agents, the time of boiling, and dispenses with the washing cylin- 

 ders for crushing. For the manufacture of unbleached papers the 

 method of crushing by vertical mill-stones, organised at Valvernier, 

 gives results which no other perhaps, can attain ; dispatch, homogeneity 

 of pulp, simplicity of operation and of working, no waste ; such are the 

 advantages of this method. For white pulp, the question varies ; the 

 mill at Valvernier does not produce fibre, it produces pulp which is taken 

 direct to be finished, and which cannot be treated with steam or chlorine 

 gas, for this will only pass through spongy and easily permeable masses. 

 Without this condition, it either does not operate, or but partially. Con- 

 sequently, for white pulp, recourse must be had to sharp-tackle in the rag 



VOL. IV. G 



