MECHANICS AND USEFUL ARTS. 80 



The fabric is composed of cotton or other fibrous substances, either woven 

 into cloth or in an unwoven state, and saturated or coated with a compound 

 of linseed oil and burnt umber, pi'eparcd by boiling in every gallon of oil 

 about three pounds of umber in a powdered state, for such a length of time 

 that the composition, when cool, will roll in the hands without sticking. 

 The fabric may be made in forms suitable for the soles of boots and shoes, 

 coverings for trunks, travelling bags, cap-fronts, or as a substitute for car- 

 riage or harness leather, or for machine-belting or hose-pipe. The mode of 

 producing the fabric differs, to some extent, according to the use for which 

 it is designed; but the general principles are in all cases the same. The um- 

 ber is stirred into the boiled oil until it reaches the point desired, when it is 

 ready to be applied, in the manner best calculated to produce special articles. 



A NE\Y CEMENT. 



Mr. Edmund Davy prepares a neAv cement, which is well spoken of, by 

 melting in an iron vessel equal parts of common pitch and gutta-percha. It 

 is kept either liquid under water, or solid, to be melted when wanted. It is 

 not attacked by water, and adheres firmly to wood, stone, glass, porcelain, 

 ivory, leather, parchment paper, feathers, wool, cotton, hemp, and linen fab- 

 rics, and even to varnish. Cosmos, vol. xii., p. 41. 



LIQUID GLUE. 



Take glue of good quality and dissolve it in as small a quantity of hot wa- 

 ter as possible ; then, while yet hot, remove it from the fire and dilute it to 

 the proper degree of thinness by adding alcohol, after which it should be 

 bottled, and the mouth of the bottle kept covered with a piece of India-rub- 

 ber, or anything else that will exclude the air. Alcohol will preserve glue 

 made in this way for many years, keeping it from putrefaction in summer 

 and from freezing in winter. In cold weather it requires only a little warm- 

 ing to make it ready for use. This convenient article has been in use in Eng- 

 land for many years, but has never been extensively known in this country. 







ARTIFICIAL IVORY. 



A patent has recently been granted, in England, to Charles "Westendarp, 

 jr., for manufacturing a material intended to imitate ivory, bone, horn, coral, 

 or other similar substances, natural or artificial, and which may be used in 

 preference to ivory, on account of cheapness and adaptability, as the same 

 materials may be moulded or turned to the various forms or patterns they 

 may be desired to take, and may be applied to all the purposes in which 

 natural ivory becomes useful, such, for instance, as billiard-balls, door and 

 other knobs, piano-forte keys, rulers, paper-knives, whip, stick, and other 

 mounts, and in imitation, or as a substitute for carved wood, enamelled 

 china, precious stone works, and a variety of fancy, ornamental, and dgcor- 

 ative figures. 



The process being as follows : Five ounces (or more or less according to 

 the size of the article to be made,) of ivory dust is soaked with a white color, 

 say white lead or zinc white, three ounces, in a solution of white shellac or 

 copal, in sixteen ounces of spirit of wine. After the whole is well mixed, 

 which is best done at a temperature of 212 Fahrenheit, the alcohol is par- 



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