270 ANNUAL OF SCIENTIFIC DISCOVERY. 



or soda, marking 6 to 10 of the areometer of Beaume', are to be applied by 

 means of large and soft brushes, at an interval of several hours. 



Upon Wood. Upon wood, the application of silicious painting presented 

 some difficulties. Woods impregnated with resin do not receive the color 

 uniformly. Wetting with the water of the solution tends to cause the wood to 

 crack. Ash and yoke-elm, however, answer very well with a few precautions. 

 Mr. Kiihlmann has been able to submit to your commission some rather old 

 paintings upon wood, which had resisted numerous washings, and the 

 intense heat of a fire, close to which they were placed. 



Upon Glass. Your commission has examined with the greatest interest 

 paintings which have been executed upon glass. Artificial sulphate of 

 baryta, applied to glass by means of silicate of potash, imparts to it a milk- 

 white color of great beauty; in a few days the silica is found intimately 

 combined with it, and the color resists washing with warm water. By the 

 action of a strong heat, this silicious varnish is transformed into a fine white 

 enamel. Blue ultramarine, oxide of chromium, and pulverized colored 

 enamels, may be applied. Silicious painting upon glass is destined to find 

 advantageous employment in the construction of church windows; whilst 

 silicious painting upon stone will serve for mural decorations. 



Following the same order of ideas, Mr. Kiihlmann has extended his 

 researches to printing upon paper and upon stuffs, to the employment of 

 silicate of soda in scene-painting and in dressing stuff's. 



Upon Paper. By grinding the finely-divided charcoal which is employed 

 in the manufacture of Indian ink with the silicate, a writing ink is obtained, 

 which is almost unassailable by any chemical agent. 



Upon Stujfs. In calico-printing, silicate of potash replaces albumen, 

 which is now employed for fixing colors. The silicious solution is mixed 

 with the colors at the moment of priming; in a few days the design acquires 

 such a consistency that the colors resist washing and soap, provided they are 

 not alterable by alkalies. 



Printing and Dressing StuJTs. From a series of experiments undertaken 

 with the view of showing that in dyeing it is not correct to assume that 

 nitrogenous substances possess a greater aptitude for receiving colors than 

 non-nitrogenous substances, and that dyeing rests essentially upon a cliemi -al 

 combination with the textile material, either in the natural state or variously 

 combined or modified, Mr. Kuhlmann was induced to replace the albumen 

 used in printing stuffs, either by a compound of gelatine and tannin, or by 

 starch-paste fixed upon the cloth by means of lime or baryta-water, or also 

 by the soluble silicates. In printing upon paper, he has succeeded in replac- 

 ing the varnish with which it is usual to cover the colors which have been 

 fixed by means of gelatine, by a layer of tannin, and even the gelatine itself 

 by starch fixed by means of lime or baryta. 



ON THE EXAMINATION OF CERTAIN MINERAL SUBSTANCES FOUND 



IN TREES. 



At a recent meeting of the Boston Society of Natural History, Dr. A. A. 

 Hayes made a report of an examination of a curious mineral substance found 

 by Dr. C. F. Wiuslow in the structure of certain trees of the Sandwich 

 Islands. 



The substance occurs in the form of hollow and sometimes solid cylinders, 

 about one fourth of an inch in diameter; small lateral holes are found opening 



