flfcw ElfBrk Experiments* l<]') 



■§i Experiments made to determine whether it was poffible 

 oy electric fparks to decompofe certain fubftances, or to 

 change them in a fenfible manner.— As Dr. Van Marum, in 

 the years 1785 and 1787, was able to decompofe nitrous and 

 alkaline air by electric fparks, he vvifhed to try the fame ex- 

 periment with other fubftances. For this purpofe he em- 

 ployed tubes of from 13 to 14 inches in length, and from. 

 3 to 4 lines in diameter, into the ends of which he introduced, 

 platina wires, and fufed the glafs around them. When the 

 bodies to be examined required mercury, he filled the tubes 

 with that fubftance, and introduced the bodies in fuch * 

 manner that they floated about an inch over it. Above the 

 bodies an inch of air was left, that the fparks might be con- 

 veyed to them with greater force ; for he had been taught, 

 by experience, that the {hocks are of the utmoft importance 

 in experiments of this kind. However, he could not venture 

 here to employ any atmofpheric air; as this air, when de- 

 compofed, gives nitrous acid, which would have mixed with 

 the products obtained. The fitteft for this purpofe were vital 

 air and azot. When he tried fuch fubftances as attack mer- 

 cury, the whole tubes were filled with the acid, and a platina. 

 wire was immcrfed in it, fo that its upper end was an inch 

 deep below the furface of the acid. This wire ferved inftead 

 of the mercury as a conductor. 



Having introduced concentrated fulphuric acid into this 

 laft apparatus, and conveyed to it, for a quarter of an hour, 

 pofitive or negative fparks, no figns of any change were ob- 

 ferved. The cafe was the fame when it was ftrongly heated 

 or rarefied. 



Fuming nitrous acid gave, in the eourfe of five minutes, a 

 column of two inches of an aeriform fluid ; but iri a quarter 

 of an hour very little of it remained. It appears that the ca- 

 loric of the ele&ric matter had given the acid a gafeous form, 

 but in itfelf no change could be perceived. 



Common nitrous at id gave a column of air of half an inch, 

 which dilappearcd alio when the electric matter ceafed to 

 i:t. 



Common fuming muriatic acid exhibited the fame phse- 

 oomtna as the former. The hypcroxygenated did not pro- 

 duce 



