204 



Flax, its Treatment, 



tion of the azotized extractive matter and also the quality of 

 fibre produced. It is well known that albuminous solutions, 

 containing even a very small proportion of albumen (1 in 1000), 

 coagulate at a temperature of 180°, and then become insoluble ; 

 and it is always considered that fibre is more or less injured if 

 exposed beyond a certain high temperature. These two impor- 

 tant points have been taken advantage of in Buchanan's process ; 

 the temperature of the steep liquor is kept between 150° and 180°, 

 and the operation, both as regards time and produce, more satis- 

 factorily performed. The process is quite automatic, thus saving 

 labour and the risks consequent upon carelessness ; and the 

 mechanical arrangements by which it is effected are very simple 

 and inexpensive. The flax straw is placed in an open vessel 

 (No. 3) termed the steeping vat, having a false bottom {%) ; a 

 boiler (No. 1) generates the steam required ; and between these two 

 is placed a suitable vessel (No. 2), the condenser, of about the same 

 capacity as No. 3, and communicating with that by the hot-water 

 pipe (6), and with the boiler by the steam pipe (a). This centre 

 vessel or condensing chamber is filled with water from the cistern 

 (No. 5), and steam is then blown in from the boiler. When the 

 latent heat of the steam is absorbed, and condensation no longer 

 takes place, the hot water is driven over into the steeping vat, 

 and completely immerses its contents. The overflow pipe (c) 

 then conveys a portion into the bucket (No. 4), which, over- 

 powering the balance weights (^ g), descends, drawing the chain 

 {e e), which, being attached to the pullies (//) fixed on to the 

 cocks of the steam-pipe (a), and of the condensing pipe (A), 

 reverses their action by cutting off the steam and turning on a 

 charge of cold water into the condenser. The steam in No. 2 is 

 then rapidly condensed, and the liquor drawn back from the 

 steep vat into which it had previously been forced. This com- 

 pletes the operation of immersion, which recommences imme- 

 diately : — for as soon as the overflow bucket (No. 4) has reached 

 a certain point in its descent it strikes against a pin, having a 

 screw adjustment, which causes the valve (c?) at the bottom to 

 open and discharge its contents into the discharge pipe (No. 6). 

 The bucket, then relieved of its load, resumes its original posi- 

 tion, the balance weights {(/(/) act on the pullies {ff), which 

 again reverse the cocks, cutting off the cold water sparge, and 

 turning on the steam to No. 2. This is repeated as often as 

 may be required. 



So far as the experiments have gone, it has been found that 

 by ten such immersions the whole of the colouring matter of the 

 flax has been removed. These in practice would not occupy 

 more than three or four hours. This, however, is subject to the 

 test of the operations on a commercial scale which are now in 

 progress in Scotland for carrying out the patent. 



