292 THE FLAX CROP. 



applied for a long time past. The first " rettery" on this 

 principle was established in Mayo in 1848; now there are 

 some twenty to thirty at work in different parts of Ire- 

 land, besides several in this country, operating upon from 

 40,000 to 50,000 tons of straw annually. In this the 

 principle of fermentation is the same as in the old process, 

 but is now totally independent of external temperature, 

 being placed under the control of the operator, who can 

 easily regulate the action of the steep according to the quan- 

 tity of flax operated upon, or the quality of the article he 

 wishes to produce. An important saving in time is 

 effected, from seventy-two hours for the finer qualities to 

 ninety-six hours for the coarser only being required, instead 

 of from two to three weeks. The work, too, can be carried 

 on all the year round, instead of only during the summer 

 months, and a more regular and certain fibre is obtained. 

 The size and number of the steeping tanks are regu- 

 lated by the general working arrangements of the " ret- 

 tery/' and these again are mainly determined by the local 

 circumstances of supply and sale. The temperature of the 

 " steep" is kept up between 80 and 90, and controlled at 

 will by the operator. Here, however, we have the same 

 destructive fermentation at work as in the ordinary steep- 

 ing, under a certain control, it is true, but generating, as 

 the decomposition proceeds, the same foul and offensive 

 gases. These gaseous exhalations, which far and near 

 stamp the unpleasant proximity of a " rettery," have been 

 examined by various chemists, and have been found to 

 consist chiefly of carbonic acid and hydrogen in nearly 

 equal parts, with combinations of both sulphur and phos- 

 phorus with hydrogen. The fermentation appears to be 

 of a peculiar character, merely traces of acetic acid being 

 found, while butyric acid is generated in large quantities. 

 In fact, the fragrant butyric ether, so extensively used 

 now as a flavouring substance, especially in the preparation 



