L. TECHNOLOGY. 451 



potato starch is to be spread out in pans of proper dimen- 

 sions, and exposed to a temperature of about 400 Falir., 

 taking care to avoid burning, and kept heated until a slight 

 change of color takes place ; practically, as long as the mass 

 remains white, some portion of the starch continues un- 

 changed, which would prevent the preparation of a clear so- 

 lution. 



' To prepare dextrine, one thousand parts of dry starch are 

 to be moistened with a mixture of two parts of concentrated 

 nitric acid and three hundred parts of water. The paste thus 

 prepared is to be dried in pieces, first in the air, and then at 

 a temperature of 140 to 150, which is subsequently to be 

 increased to 280. This substance is considerably whiter 

 than that obtained by heating, but in most cases contains a 

 small portion of starch, which can easily be determined by 

 reaction with iodide of potassium. 



The above substances, in one combination or another, are 

 used not only for purposes connected with jmnting, but also 

 as sizes, and very largely in the preparation of the mucilage 

 now to be found on every office table. 25 C, 1871, 177. 



PEEPAEATION OF ALBUMEN FEOM ELOOD. 



The preparation, on a large scale, of albumen from blood 

 is, we learn, carried on successfully at establishments in 

 Korth Germany and Hungary, and it is furnished at one 

 half the cost of egg albumen, although equal to it in all re- 

 spects except color. It is said that three thousand pounds 

 of blood will yield one hundred and ten pounds of albumen ; 

 and it is thought that, by proper care of the immense quan- 

 tities of blood every day wasted, an ample supply can be fur- 

 nished, which is not the case at the present time, compared 

 with the extent to which albumen is required for refining 

 sugar, sizing goods, etc. 15 A.July 29, 149. 



DYEING WITH ACIDS IN BEASS KETTLES. 



The substance of the vessel in which articles are to be 

 dyed is of considerable importance, especially where acid so- 

 lutions are employed. Brass kettles are most generally used 

 for such operations ; but scarlet, as well as some other dyes, 

 in which acids are used, can not well be introduced into such 

 a vessel. Reimann's Journal of Dyeing advises, in this case, 



