516 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the matrix was a diapositive. After the picture has been 

 developed so that the lights are entirely pure, the stone is to 

 be moistened with alum water, and then allowed to dry. If 

 the experiment has been successful, the negative picture will 

 appear clear and sharp after drying. The edges of the stone 

 are now to be gummed in the ordinary way, and the stone 

 rolled with lithographic black, after which it is to be well 

 rubbed down with a folded flannel cloth dipped in gum wa- 

 ter; the gelatine of which the negative picture was composed 

 is removed, and the fat color remains on the originally clear 

 spaces. If the experiment has succeeded, a positive of great 

 delicacy will be produced, which can then be printed from. 

 18 C, March 6, 1872, 155. 



^ ^ 



USE OF CASEINE IN COTTON PKINTING. 



The use of caseine as a thickening material in cotton print- 

 ing continues to increase in favor, the substance being applied 

 by adding a very little cold water to the caseine, and about 

 two to three per cent, of magnesia, giving a thick and gum- 

 my solution, which runs when exposed to heat, but not in the 

 cold, the melted mass being soluble in alkaline liquids. When 

 insoluble colors are printed with this solution they become 

 fixed, in consequence of the running produced by steaming. 

 The colors, however, will not wash. If the caseine is treated 

 with a larger quantity of magnesia, say from five to ten per 

 cent., we do not have a solution, but a thick, semi-fluid, ho- 

 mogeneous paste, which can be stirred around in water with- 

 out giving a true solution. In barytes water, however, this 

 paste becomes a thin, gummy solution, which is well adapted, 

 in certain cases, for thickening. This melts almost complete- 

 ly by heat, and the mass is insoluble in alkali. The solution 

 can be kept for a long time without decomposition, but must 

 be protected against the carbonic acid of the atmosphere, 

 which will gradually cause the barytes to precipitate, and 

 thus diminish the solubility of the magnesian combination. 

 25(7,1871,363. 



WATEE-PEOOFING CLOTH. 



Cloth and other fabrics can, it is said, be made water-proof, 

 and at the same time secure against the attack of moths, by 

 the following preparation : Ten pounds of sulphate of alumin- 



