34 



FOSSILE ALKALI. Sept. 1 4,' 



not tinged filver, which has been kept in contaft with it thefe 

 feveral days*. 



It fhould feem from thefe clrcumftances, that there is very 

 little fulphur remaining in the foda, and muft be at leaft great- 

 ly weakened. 



When the hepar fulphuris is diflblved in water, the fulphur, 

 being fcarcely foliible in 'water, is in part difengaged from the 

 alkali, and finks to the bottom. 



While the folution is evaporating, more of the fulphur Is 

 feparated, and adheres to the fides and bottom of the vefTel. 

 This may be removed by conveying the folution into another 

 veflel, when the procefs of evaporation draws towards an end. 

 A part of the fulphur which ftill remains, is probably volati- 

 lized in the furnace before the heat becomes fo ftrong^as to 

 burn it. In fhort, by the various parts of the procefs, fo little 

 fulphur remains, that the alkali may be applied to many ufeful 

 purpofes. Though aCbes muft always be valuable in propor- 

 tion to their purity, yet it is not abfolutely neceffary, that, in 

 every cafe, they fliould be perfectly free from fulphur. By exa- 

 • mining the lies of American pot aflies, you will find, that they 

 contain a conCdevable deal of fulphur, and yet they are very 

 ufeful in bleaching. 



Without faying any thing of the glafs-houfe, or the manu-- 

 fafture of common foap, the foffile alkali, feparated according 

 to my direftions, will, I hope, be found to be beneficial for 

 boiling or bleaching llrong goods in the firft ftages of bleach- 

 ing. 



It is fcarcely necedary to remark, that the purity of the 

 ibda, either with refpeft to fulphur or neutral falts, muft de- 

 pend upon the degree of accuracy which has been obferved in 

 condudlng the operation. 



I by no means fuppofe that my fcheme is free from imper- 

 fe(Elions, but it has at leaft novelty to offer in alleviation of its 

 defers, and time aided by experience will, it is hoped, render 

 it more worthy of approbation. 



* Since the above was written, I have made fome farther ex- 

 periments with ftill greater accuracy ; the refult is this : In no 

 cafe have I ever found that the alkali obtained by my procefs 

 has, in its dryjtate, tinged filver, and in one cafe a folution of it 

 in water did not affedt filver ; but I have fince made lie of the 

 alkali that does tinge filvtr a little; 



