210 ANNUAL OF SCIENTIFIC DISCOVERY. 



a stamping ink for goods before undergoing bleaching, or treating 

 with acids or alkalies. It consists merely of one ounce of fine Chinese 

 vermilion and one drachm of protosulphate of iron, well triturated 

 with boiled oil varnish. 



To remove Ink from Paper. M. Piesse communicates to the 

 Scientific American the following process for removing writing ink 

 from paper: Alternately wash the paper with a camel-hair brush 

 dipped in a solution of cyanide of potassium and oxalic acid ; then, 

 when the ink has disappeared, wash the paper with pure water. 

 By this process checks have been altered when written on " patent 

 check paper," from which it was supposed by a recent inventor to 

 be impossible to remove writing. 



MANUFACTURE OF PHOSPHORUS. 



M. Caie Montrand, applying the knowledge of the fact that, under 

 an elevated temperature, any phosphate of lime mixed with charcoal, 

 subjected to the action of hydro-chloric acid gas, is decomposed, has 

 based upon this reaction a new industrial process for obtaining phos- 

 phorus. Burnt bones, reduced to a fine powder, are mixed with 

 wood charcoal in earthen cylinders. AYhen these are raised to a red 

 heat a current of hydro-chloric acid gas is introduced. The phos- 

 phate of lime is immediately decomposed, and chloride of calcium, 

 carbonic oxide, hydrogen, and free phosphorus are formed. The last 

 is distilled off and condensed. 



IMPROVED DISINFECTANT. 



M. Agata, of London, has patented the process of this preparation. 

 He collects the common cockle and other shells found on the sea- 

 shore, and calcines them in a furnace until they are reduced to a 

 friable condition, and readily broken and powdered. To this powder 

 he adds, first, half the quantity of sulphate of iron, thus producing 

 a fine yellow, inodorous powder, resembling ochre. The material is 

 inexpensive, and it is quick and economic in its action, as it requires 

 but about one part of the disinfectant to one hundred of the matter 

 to be treated. It is more especially intended for all kinds of feculent 

 matter, etc. ; when used as a disinfectant for urine, about two per 

 cent, of common tar is to be added. 



WHITE GUNPOWDER. 



Considerable attention has been given of late to this substance. 

 M. Pohl, a German chemist, in a communication to the Academy of 

 Vienna, states that prussiate of potash 20 parts, sugar 23, and chlo- 

 rate of potash 49 parts, make good white gunpowder. In exploding 

 this powder, 100 parts of it yielded 47.44 of gaseous products and 

 52.56 solid residue. Ordinarily black gunpowder furnishes only 

 31.38 of gaseous products and 68.06 of solid residue. The efficiency 

 of gunpowder is measured by the gases which are produced from it 

 by explosion. An equal weight of white gunpowder will produce 

 1.67 times the explosive effect of the black. In order to obtain the 

 same effect on projectiles and in mines, only 60 parts of white pow- 



