M. TECHNOLOGY. 487 



COPYING APPARATUS OF BAUER & CO. 



A coiDying apparatus, manufactured by Bauer & Co., of 

 Vienna, consists of a metallic tablet framed in wood, and 

 covered with a paste containing aniline violet, or red. By 

 tracing with a pencil or style on paper laid upon this, enough 

 of the material will be taken up by it to yield copies on 

 moistened paper, by laying the latter on it and patting it 

 with the hand. The results, however, are very limited in 

 quantity and quality, since the j^aper is not strong enough 

 to yield even fifty copies. G C, January 20, 187G, 28. 



PAPIER-MACIIE ORNAMENTS, ETC. 



Some English papier-inaclie articles are remarkable not 

 only for their form and general appearance, but also for their 

 durability. They are manufactured by first pressing a sheet 

 of very porous but strong paper, manufactured expressly for 

 the purpose, upon the metal greased with tallow. This is 

 then coated with good flour paste and a second sheet is laid 

 on, and pressed and rubbed until it takes the form of the 

 model and adheres firmly. The whole is then placed in a 

 drying-chamber at about 104, and then the operations of 

 laying on and drying are repeated until the desired thickness 

 is produced twenty to forty sheets being frequently required 

 for the purpose. The form is then removed, all the sides are 

 carefully adjusted, and the article is then hardened by first 

 immersing it in linseed-oil and purified wood-tar, and coat- 

 ing six to eight times with varnish, allowing it to dry thor- 

 oughly after each coat. It is finally ground down with pum- 

 ice-stone, and ornamented with bronze, gold, or mother-of- 

 pearl. Cheaper articles are manufactured from a species of 

 paper pulp with certain proportions of white-lead, rosin, lin- 

 seed-oil, and sugar of lead, carefully kneaded and rolled by 

 the aid of steam. This is then pressed into moulds and 

 dried. The most ordinary articles are made of pulp and earth 

 colors, with the addition of some hardening cement. 5 6', L., 

 400. 



PRESERVATION OF PLASTER CASTS. 



Mr. John Bell communicates to the Society of Arts the 

 statement that the thorough saturation of plaster in melted 



