166 Process employed to obtain a Black Liquid. 



is no longer of a blue cast, but rem;iins perfectly limpid. 

 The residue, i. e. this powder, well dried, will be silver in it* 

 purest state. 



If this residue weighs one ounce, dissolve as much gum 

 Senegal and two drachms of white glue in two ounces of 

 distilled water. Mix this solution with three drachms of 

 lamp-black well calcined in a clo?e crucible. 



To manufacture this n)ixture properly, it ought to be tri- 

 turated in a glass mortar. 



This operation bejng finished, the solution of silver, di- 

 luted in eight times its weight of distilled water, is poured 

 npon the above mixture : the whole is then well stirred with 

 a spatula, and the ink is madf. 



Preparation of the Mwdant. 



Dissolve two ounces of white cfUie and as much isinglass, 

 in six ounces of alcohol and as much distilled v/atcr. This 

 solution will be made in two davs. The B. ^I. is uiadc; use 

 of for the purpose; and care must be taken to stir the two 

 kinds of glue from time to time. 



After the whole is dissolved, it must be flllered through 

 flannel, in order to keep back all its mucilaginous panicles. 

 The liquid thus filtered, and preserved in a botlle well corked, 

 is then ready for use. 



Manner in n hich the Ink acts. 



The solution of silver in the nitric acid is nothing else 

 than the composition of the lapis i/ifcrnalis ; and every one 

 knows its properties in staining the skin, nails, &c., of a 

 black colour. If the linen or stuff" is first impregnated with 

 the above mordant, which is an animal substance, the ink 

 may be afterwards applied without spreadins, and will com- 

 pletely dye every thread of the part to which it is applied, 

 the mordant having previously partly animalized the fibre of 

 tlie fabric. 



Soap, or any other ingredient used in washing, may obli- 

 terate the lamp black, but it never takes out the nitrate of 

 silver; and the object proposed is therefore perfectly well 

 attained. 



Application 



