140 Chemico • Galvanic Observations* 



ofalthea, and troubled a little the solutions of mercury and 



silver. 



After washing the zinc employed in the above experiment 

 in distilled water, the same process was repeated with it se- 

 veral times, and always with the same effects. 



Filings of copper and of iron, treated in the same manner^ 

 also produced an alkaline substance in water. Mercury it- 

 self, after a long agitation in distilled water, also produced 

 alkali in this liquid. We know that Priestley remarked that 

 he had also formed a black oxide of mercury in water, and 

 that the water acquired both smell and taste ; but the alka- 

 line matter which was formed or disengaged in his experi- 

 ment had escaped him. 



The pulverulent substances which are deposited in water 

 in which metals have been agitated are oxides of the greatest 

 tenuity. That of zinc is gray ; that of copper brown ; that 

 of iron and mercury is black. And as the air contained in 

 the phials in which these metals are agitated undergoes no 

 sensible change, it appears evident that by this process the 

 metal is united to the oxygen of the water, without any ap- 

 preciable quantity of hydrogen gas being disengaged. 



The water rendered alkaline by the processes which we 

 have mentioned greens the purple tincture of althea; but if 

 it is allowed to settle some hours upon these same metals, it 

 loses its alkaline properties. It must follow, then, that the 

 alkali is either decomposed, or that -it enters into some new 

 combination. 



In order to determine the nature of this alkali, the author 

 poured a little muriatic acid upon water alkalized by mer- 

 cury and by zinc, and filtered. He afterwards evapo- 

 rated it, and obtained a salt in short and transverse spicula; 

 but.it was in too small quantity to determine its nature with 

 certainty. He ascertained, however, that it was not soda ; 

 and he had ev:ry reason to believe that it was muriate of 

 ammonia. 



General Re/lections upon the preceding Observations. 



" Some of the facts," says M. Brugnalelli, " communi- 

 cated in this paper, and which are singular in themselves, 



may 



