522 ANNUAL RECORD OF SCIENCE AND INDUSTRY'. 



i 



is to be applied as already indicated until there is no further 

 usty tinge to the escaping oily matter. 

 Should the sewing-machine have become very much closed 

 through long disuse by dust and hardened oil, after a prelim- 

 inary treatment with the fat referred to, spirits of turpentine 

 or benzine may be applied to good advantage. 16 C, V., 

 1871,189. 



COLORING TIN-FOIL WITH ANILINE. 



Tinted tin-foil is much used by confectioners and others 

 as an ornamental wrapper for their goods. Springmiihl rec- 

 ommends aniline colors, soluble in water, as best adapted to 

 preparing this material of the desired hue. The tin-foil is 

 placed upon moistened plate-glass and carefully smoothed by 

 means of a polishing stone. A limpid solution of white gela- 

 tine, colored to the desired shade, is then poured over the 

 metal so as to cover it evenly, the surplus being drained off 

 by lifting one edge of the glass. The drying is to be done 

 rather rapidly. To render the colors water-proof, they must 

 be covered by a resinous lacquer. 25 C, xix., 1872, 149. 



COLLODION LACQUER. 



Solutions of resins and gums, colored with aniline, are now 

 extensively used as varnishes, though they do not always 

 give entire satisfaction; and Springmiihl has lately ascer- 

 tained that collodion in many cases is better adapted for pro- 

 ducing a transparent, firm, and water-proof coat, especially 

 upon glass, mica, metal, etc. His process is as follows : Gun- 

 cotton, specially prepared for the purpose, is dissolved in a 

 mixture of two parts by volume of ether and one of alcohol 

 of 95 per cent. The thick, clear mass thus obtained is further 

 diluted with ether, and the aniline color, dissolved in pure 

 alcohol, added, and thoroughly incorporated by shaking to- 

 gether. The proper degree of dilution is essential for suc- 

 cess ; otherwise there will be no difficulty, the manipulation 

 being simply that of the photographer when preparing his 

 plates, viz., pouring the collodion over the surface to be 

 coated, which has previously been well cleaned. The dry- 

 ing proceeds rapidly, and the thin, transparent film adheres 

 firmly, so as to recommend the process especially for the 

 manufacture of colored tin-foils. 25 C, xx., 187. 



