128 TEXTILE FABRICS. [V. 



(with 400 pts. for flax), and, after a time, is removed and put 

 on a lattice. The operation is repeated in the course of 5-6 

 hours, and oftener, until the retting is complete, which is 

 indicated by black spots on the stems. It is then rinsed 

 thoroughly in water, passed through a bath of 1 pt. potash 

 in 10,000 pts. water, to neutralize any remaining acid, and, 

 lastly, rinsed in clean water, and dried. 



Hemp and Linen, with New-Zealand Flax. — New-Zealand 

 flax diminishes the value of cordage, &c. made of hemp or 

 flax, rendering it less durable. Vincent gives the following 

 method of detecting the mixture. (Comptes Rendus, 1847.) 

 Hemp fibre, dipped for a few seconds into nitric acid, is 

 colored pale-yellow, linen not at all, and New-Zealand flax 

 blood-red. A piece of cloth, containing both flax and New- 

 Zealand flax, dipped into the acid, showed red striae in the 

 woof and none in the chain, which was all common flax. 



To detect Cotton in Linen. — Eisner has published a critical 

 review of the various methods proposed to distinguish cotton 

 and flaxen fibres (Berlin. Industrie u. Handelsbl. xxiv.), the 

 best of which we extract from his report. Stockhardt ob- 

 served that a flaxen fibre, inflamed in a vertical position, and 

 then extinguished, appeared to be carbonized at that end in a 

 smooth, coherent shape, while cotton, similarly treated, ap- 

 peared to be spread out like a brush or tuft. Eisner observes 

 that it especially occurs when the flame is violently blown out, 

 and that it succeeds with dyed goods, unless dyed by chrome 

 yellow. 



The potash test consists in putting the fibre into boiling 

 caustic potassa-lye for a couple of minutes, when the flax turns 

 deep-yellow and the cotton is scarcely changed. The test is 

 not reliable. 



One of the best is the microscopic examination, for when 

 flax is magnified 300 times, it appears like long, compact tubes, 

 with a narrow channel in the centre, while cotton appears to 

 be fiattened, ribbon-like cylinders, with a wide channel, and 

 mostly in spiral windings. 



The test with oil of vitriol is reliable in an experienced 



