MECHANICS AND USEFUL ARTS. 89 



peratiu-c of 340° Fahr., it is consumed, without flame, being decom- 

 posed and passing off as dense smoke, leaving but a dark colored 

 ashy residue behind. It is now being manufactured for a variety 

 of purposes, and is daily becoming more extensively known. — ». 

 Mining Journal. 



At the 1865 meeting of the British Association, ]Mr. Owen Ro- 

 land read a jjajier on Parkesine. This substance derives its name 

 fi'om its inventor, Mr. Alexander Parkes, of Birmingham, Eng. 

 It is used for a great variety of purposes, and j^ossesses properties 

 akin to gutta-percha and India-rubber, and may be made easily 

 into any shajje and of any color. Gun-cotton is used in its manu- 

 facture as a basis ; but many other materials are also introduced, 

 solvents, oils, cotton-waste, etc. Cotton, not readily explosive, is 

 the most desirable ; chloride of zinc is also used to j^revent rapid 

 combustion. The solvent, invented by Mr. Pai'kes is apj^licable 

 cliiefly for India-rubber solutions, gutta-percha, and a number of 

 gums. The several varieties of Parkesine are made by mixing 

 these substances in definite pi'oportions. Mr. Roland considered it 

 more valuable as an insulating material thau India-rubber, gutta- 

 percha, or any other comljination hitherto used for this purpose. 

 It is enormously strong, being capable of supporting a mile of its 

 own weight, while it possesses the great qualification of Ijeing 

 joined, in case of fracture, with a strength equal to the original 

 substance. It is not affected even by acids ; and immersion in sea- 

 water four years did not deteriorate its qualities. In dry heat, at 

 212° Fahr., it remains electrically perfect, and it is not softened at 

 even a higher temperature. 



INDIA-KUBBEE FOR MARINE CABLES. 



At the Nottingham (1866) meeting of the British Association 

 for the Advancement of Science (Section of Physical Science), 

 Mr. Hooper read a paper on the electrical and mechanical prop- 

 erties of his India-rubber for submarine caljles. He reduces the 

 general coatings of India-rubber by means of heat to one perfectly 

 homogeneous coating, separated by a film of vulcanized India- 

 rubber. The advantages claimed are, durability and resistance to 

 mechanical injury, permanency of insulation at high temperatures, 

 impermeability under long immersion and pressure in water, free- 

 dom from defects in manufacture, and high state of insulation 

 Avith diminished induction. One hundred and fifty miles of this 

 wire have been sent to India, and the insulation per nautical mile 

 is about forty times better than that of the Persian Gulf core. 



PAPER FROM WOOD. 



• 



The manufacture of white paper from wood is now quite a 

 success at the Manayunk Wood-pulp Works, Pennsylvania. The 

 wood used is that of the Liriodendron ^wZ/pZ/ej-a, Linn., in Tulip 

 poplar, and Abies canadensis, Michx, or Hemlock spruce. It is 

 brought to the works as ordinary cord- wood, and is cut into chips 

 by means of two immense machines having cutters attached to 

 8* 



