114 THE CANADIAN NATURALISE. [March 



way as to allow the positive wire to plunge into this acidulated 

 liquid, taking care to leave a small interval between the extremi- 

 ties of the wires ; the electric current thus established through the 

 acidulated fluid as a conductor, produces the following phenomena. 

 Very soon the extremity of the positive wire takes a conical point 

 of more or less sharpness, depending on the free distance existing 

 between the two wires plunging into the acidulated liquid. Dur- 

 ing this phenomenon, which takes from 5 to 15 minutes, according 

 to the acid used, its strength, the coinposition of the wire, its 

 degree of thickness, and also the intensity of the electric current, 

 very fine sections of the wire are seen to separate from the wire. 

 Water, acidulated with sulphuric acid, appears to be more effica- 

 cious, especially for iron and steel wires. Nitric acid is used in 

 preference for brass and copper wires. The same effect will take 

 place if to the positive pole (superior) an indefinite number of 

 wires are tied together and dipped in the acidulated water, instead 

 of the single wire, care being always to keep this positive wire at 

 a Httle distance from the negative wire. I have seen a hundred 

 brass wires after having been submitted to this operation, present 

 points as sharp as the best English pins, although the electric 

 current was produced by a very small Bunsen's battery. It ap- 

 pears to me very desirable that this new method should receive 

 proper encouragement, and everything should be tried to bring it 

 into general use. The operation of making the points of needles 

 and pins in their manufacture is a dangerous and costly one. 

 Medical men in large manufacturing cities have long recognized 

 the dangerous eff"ects produced by the fine metallic dust resulting 

 from it, on the health of the workmen. The remedies for this 

 evil are very imperfect, little used, and very impracticable; in- 

 haling apparatus communicating with the outside air has been 

 tried, but every danger would be suppressed by the method above 

 described. — Scientific American. 



Another New Dye. — The aniUne dyes, it seems, have now 

 a rival which not only vies with them in brilliancy and variety, 

 but is of a less fleeting or more fixing character. The new 

 colouring matter, according to the Mechanics' Magazine^ is a pure- 

 ly vegetable extract, the plant from which it is obtained being 

 imported from the western part of Africa, and also from the West 

 Indies. The colouring matter is variously treated, according to 



