}202 «N' TANIN AND ITS SPECIES. 



Fujlet. 



Fuftet, It is a pure dyeing extract foluble in water as well as in af- 



cohol. It contains a fmall quantity of gallic acid, but does 

 not change the folution of glue. It reduces gold, precipi-. 

 tates the metallic falts, and has no gummy portion. 



Grains of Avignon, or French Berries. 

 Gr. d'Avignon, They afford a dyeing extract of the fame nature, without 

 ma. '" £ um or tamn « J 1 reduces gold, &c. 



Brazil Wood, 

 Braxll wood. Affords alfo a dyeing extract foluble in alcohol without 



tanin, or gum, reducing gold and precipitating the metallic 

 falts. 

 Rrduaion of Mr. Proufl has remarked, that the reduction of gold has 



five ch£#erof ceafed to be a char a«eriftic quality, fince he obferved the 

 tanin. muriatic folution abandpn this metal tp all the tinging fub- 



fiances, fuch as anjfe, cochineal, gum guttae, gallic acid, 

 verjuice, wine, vinegar, the juice of all fruits, manna, gum, 

 and fugar, though fqmewhat flowly. 

 Concluding ob- The author concludes by ohferving, that tanin has its va-, 

 rieties }ike the other immediate products; that the property 

 of precipitating glue is the generic indication, by which they 

 are diflinguifhed from extracts, which do not alter that tub- 

 fiance ; and laftly, that the different fpecies of tanin, par r 

 Tan'mg matters ticularly thofe which have been difcovered in the barks of 

 re ?"! r f t0 *' trees, cannot be compared together as to their force and their 

 preparation of ufeful qualities, but by obfervations upon fkins which have 

 leather. been fubmitted to their action. 



Sulphate of lime Note. Plafter mufl be infinitely common in vegetables. 

 VCry C bi T, r° n ^ ^ r * ^ rou ^ bas found it in verjuice, grapes, apples, goofe. 

 berries, &c. 



B. L. 



XI. Dcfcription 



