" Expertntenis Oft the Oxidation of ATetaJs by Eh^ridtft r^ 



EXPERIMENT XVII. 



Wires of different diameters were takfen, V^ith a view to try what degree of fufion 

 was required to caufe the greatefl abforption of air, or, in other words, to make the moft 

 complete oxide. 



The fame degree of ftrength of charge wa's direfted through wire of ^-^ inch diameter ; 

 no air abforbcd ; the wire was only red hot. 



Wire of -r4^ ^^s exploded and converted into balls ; the mercury rofe o-^s 



TTo converted into very fmall powdered balls - - Ot^ 



" TTo- into flocculi and balls - - - - i . 



j^ into an impalpable powder of reddifti brown colour - 1^% 



EXPERIMENT XVIII. 



Copper. 



Thirty- two inches of copper wire, of one 260 part of an inch diameter, was prepared in 

 Fjg. 4, and exploded by five difcharges } the mercury in the gage rofe i^Jg inches. 



It was converted into an impalpable powder, of a purple brown colour; the rsfiduc of" 

 air extinguilhed the flame of a fmall wax taper twice. 



This metal burns with a green flame when exploded* 



All the foregoing experiments were made by myfelf, at my houfe in Poland Street ; bWt' 

 the following were made at the houfe of Mr. Campbell, in South Audley Street, whd' 

 honoured me with his aflSftance. The apparatos we ufed were of my own cOnftruftioni 

 being a double plate machine ; each plate twenty-fix inches diameter, and a double battery 

 of thirty jars of my. common fize, containing abou*: thirty-four fquare feet coated glafj. 

 The eledlrometer was the fame as I have defcribed in Nicholfon's Jiurnal, Vol. It. 

 page 528, excepting that inftead of ufing pins of certain weights to put into B, the arm 

 C B was divided into grains, with a Aider upon it, which was fet to the weight required^ 

 as I commonly make them at prefent } being more convenient. 



EXPERIMENT XIX. 



Pure Silver. 



Forty-fJA^e inches of filver wire, of y^ part of an inch diameter, was exploded by five dif- 

 charges; the Aider upon the eleftrometer was fet at forty grains ; it was converted into an 

 impalpable black powder: the mercury rofe in the gage about half an inch, and the flame 

 of the taper was extinguiflied nine times. 



Silver burns with a greenifh flame, nearly refembling that of copper. 



Vol. v.— July 1801. U EXPERtMEt^t 



