480 Scientific News, Accounts of Booisf &t. 



obvloufly inimical to the written evidence of the moft important contrafts in human fo- 

 ciety. Many German chemifts have made experiments with their ufual intelligence and 

 fkill to refolve this problem. Among the receipts for this purpofe the following are the 

 principal * : 



1. By Weftrumb. Boil one part of Brazil wood, and three parts of pounded nut galls, 

 with forty-fix parts (the whole by weight) of pure water. When the liquid is reduced to 

 thirty-two parts, pafs it through a drainer while hot upon one part and half of very pure 

 fulphace of iron, one part and quarter of gum arabic, and a quarter of a part of fine fugar. 

 When all thefe fubftances are diflblved, add one part and a quarter of good indigo ground 

 as fine as poflible, and three quarters of a part of purified lamp black. 



As the indigo is the ingredient in this ink which refills the oxygenated acid, and as it is 

 only mechanically fufpended, it is of importance that the fluid Ihould be ftirred well every 

 time it is ufed, left the black colour of the fluid Ihould deceive the writer. 



2. By Bofle. Boil for about a quarter of an hour, one part by weight of Brazil wood, 

 with twelve parts of water. Add half a part of allum, evaporate the whole to eight parts, 

 and mix one ounce (q. part ?) of mangancfe, levigated to a very fine powder, and half a 

 part of powdered gum arabic. 



3. Apparently by the editor of the Annales. Boil for eight minutes one part by weight 

 of Brazil wood, with three parts of powdered nut gdls in nine parts of vinegar, aind an 

 equal quantity of water. After draining the liquid, diflblve therein half a part of fulphate 

 of iron, and one part of gum arable, after which add a folution of half a part of indigo 

 in one part of concentrated fulphuric acid. The oxygenated muriatic acid, if applied, will 

 diflblve the oxide of iron in this ink, but it cannot decompofe the indigo, and the great 

 objeft is to prepare the ink in fuch a manner, as that it fhall not be difchargcd by 

 that means. 



4. The fame editor alfo obferves, that the common ink may be rendered incapable of 

 being completely difcharged by any aftion which the paper can withftand, if inftead of 

 water, or other liquids, the exprefled juice of green vegetables be ufed ; fuch for example 

 as the lathiris linn, the fambucus niger, or common grafs. 



* Annales dcs Arts et Manufafluies II. 106. 



