472 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



of the fluid. The discharge can be made in this way in about 

 half the usual time. 3 A, July 27, 1872, 52. 



NIGHT-VIOLET A NEW COLOR. 



A new coloring matter, called night-violet, is prepared by- 

 digesting fuchsine for twelve hours with iodide of methyl, 

 alcohol, and caustic soda in an apparatus furnished with an 

 inverted condenser. The mass, taken from the apparatuses 

 boiled for a long time with strong soda lye, which removes 

 all the iodine, leaving the violet as a cake, which is to be dis- 

 solved in a mixture of sulphuric acid and water, and then 

 precipitated by addition of a small quantity of soda. The 

 cake so obtained is washed with a little cold water, dissolved 

 in boiling water, filtered, and the color precipitated with salt. 

 The violet so prepared appears of its proper color by artificial 

 light, 21 A, June 20, 1872, 531. 



BRILLIANT AND ECONOMICAL STARCH. 



A brilliant and economical starch finish is made by taking 

 one pound of wheat starch and stirring it up carefully in six 

 pounds of cold water until it is reduced to a homogeneous 

 paste. One ounce of aqua ammonia is then to be added by 

 constant stirring, after which the paste becomes slightly yel- 

 low and swells considerably. It is next to be diluted with 

 five pounds of cold water, and then brought nearly to the 

 boiling-point, stirring continually. After a quarter of an 

 hour at this temperature all the surplus ammonia will have 

 become volatilized, and the mixture will be found to furnish 

 an economical size, useful for a great many purposes. Linen 

 starched with this not only becomes stiffer, but much more 

 lustrous. It may also be used for coating wood to be pol- 

 ished, as it completely closes the pores. 9 1?, March 14, 1872, 

 350. 



SAFETY WRITING-INK. 



A patent has been taken out in London for the preparation 

 of an improved safety writing-ink, which consists in the ad- 

 dition, to any ink, of a solution of yellow prussiate of potash. 

 Any attempt to remove this ink by means of oxalic acid or 

 other substances changes it to a Berlin blue. 14 C, CCV., 

 176. 



