Processes in the Useful Arts. 337 



Steep or boil the flax or tow in a weak solution of subcarbonate of potash 

 or soda, in order to extract the colouring matter, rosin, &c. and wash it 

 thoroughly from the alkali. In order to prepare the bleaching liquor, re- 

 duce perfectly fresh burnt charcoal of soft porous wood, as willow or fir, 

 to a very fine powder ; tie up the powder in a bag made of cloth of a close 

 texture, immerse it in cold soft water, and wash it by pressing it with the 

 hands, till such a quantity is diffused through the water, that, on rinsing 

 a little flax through it for a few minutes, and then withdrawing it, it shall 

 be lightly blackened. Put into it the flax to be bleached, taking care that 

 each parcel shall imbibe it to its middle. When the whole is in the li- 

 quid, the water should appear clouded by the charcoal upon being well 

 shaken. Mr Emmett always used about half an ounce of charcoal to six or 

 seven pounds of flax. In order to bring the charcoal in contact with it, 

 the flax should be pressed under it several times a-day, and the liquid well 

 agitated. After about twenty or twenty-four hours, the flax, when taken 

 from the liquid, should be well wrung, and then put into a second vessel 

 of water containing less charcoal, agitated and pressed down as before. If 

 this process is well conducted, two or three days will be found sufficient. 

 It should then be spread thinly on the grass, taking care to turn it fre- 

 quently for a few days. The flax must then be rinsed in river water, 

 and washed thoroughly with soap in hot water, till it is quite clean. The 

 soap must then be washed out with cold water, and the flax dried, ex- 

 posed to the sun and air. Mr Emmett very liberally offers to supply any 

 person with samples perfectly prepared, by addressing him (post paid) at 

 Great Ouseburn, near Boroughbridge, Yorkshire. Abridged from the 

 Phil. Mag. No. ii. p. 119. 



6. Dr Zimmerman's Safety Gun. 



Several of the German Journals contain high eulogiums upon an inven- 

 tion by Dr Zimmerman, by which fire-arms are prevented from the possi- 

 bility of going off either by accident or carelessness, or in any way, without 

 the positive will of the person using them ; at the same time that it does 

 not impede or delay for an instant the use of the arm when required to act. 

 Dr Zimmerman has obtained a patent for his contrivance in some of the 

 German States. 



Although we do not know the details of this invention, we have no he- 

 sitation in informing our readers, that Dr Zimmerman has been anticipated 

 in the accomplishment of this object, by our ingenious countryman the 

 Reverend Mr Somerville of Currie, who, upwards of two years ago, obtain- 

 ed a patent for several beautiful methods of preventing the accidental dis- 

 charge of fire-arms. We have no doubt that Mr Somerville has exhausted 

 the subject, as will be seen from the description which we have given of 

 his contrivances in this Journal, No. iv. p. 316. We are glad to find 

 that these safety guns are in great demand, and that the sale of them is 

 likely to defray the great expence at which they have been brought to their 

 present state of perfection by the inventor. The guns thus fitted up may 

 be seen at Mr William Maclachlan's, gunmaker, 39 Nicholson's Street, 

 and at Messrs Robert Wheeler's and Son, gun-manufacturers, Birmingham, 

 VOL. VI. NO. II. APRIL 1827. Y 



