jro Gahanifm,—Eorian Harp, 



of flint-glafs, hermetically clofed, the pewter is oxided, but the oxide of lead of the flint-glaffr 

 is decompofed, and the glafs becomes black. 



The philofophers who have attributed thefe phenomena to eleftricity, aflert, in fupport 

 of their opinion, that they take place when the metals are j.oined by a confiderably long 

 chain. Cit, Fabi oni has determined the limits of this chain at 6 or 7 metres. Beyond that 

 diftance thefe phenomena are no longer perceptible} oa the contrary, the eledlrical fluid i» 

 propagated at unlimited diftances. 



If the phenomena in the experiments of Sultzer be really produced by eledlricity, they 

 fhould take place with all metals, what relation foever thefe <netals might otherwife have to 

 each other. Cit. Fabroni mentions a great number of thefe combinations, in which no 

 effect was produced, and of other combinations of the fame metals which have produced 

 very diftin6l fenfations. Thus, if filver be placed on the eye, gold on the tongue, and they 

 are united by means of copper, the fenfation is extremely flight; but, on the contrary, it is 

 very evident, if iron touches the eye, filver the tongue, and copper be ufed to form the 

 communication. 



With regard to the hydrogen of the decompofed water, the author of this Memoir thinks 

 it may alfo be abforbed by the metal. He even confiders the odtahedral cryflals which he has 

 bbferved on the furfaces of the pieces of tin he employed in his experiments as the hydro- 

 genated oxide of tin. 



" It is evident from thefe refults which . I have obtained by the fimple conta<3: of metals 

 in water," fays Cit. Fabroni, " that is to fay, the oxide and faline cryftals, that the operatioa 

 is chemical, and that we ought to attribute the fenfations which are felt on the eye and tongue 

 to a chemical caufe. It therefore appears probable to me, that it is to thefe new compounds 

 and their elements we owe that myfterious ftimulus which produces the convulfive motion 

 of the animal fibres in a great part, at leafl:, of the galvanic phenomena." 



IX. 

 On the J^arp o/Eelus. By Matthew Tqung, B. D. 



To Mr. Nicholson. 



o. 



Sir, 



'BSERVING a paflage in a note at p. 12. of your fecond volume, refpei^ing the harp 

 of Eolus, in which you offer fome conjeftures refpedling its mode of operation, I have 

 thought it might be acceptable to you and your readers to point out fome good experiments 

 on that inftrument. They are to be found in " An Enquiry into the principal Phenomena of 

 Sound and mufical Strings, by Matthew Young, B.D. Trinity College, Dublin." The work 

 is an odavo of 203 pages, and was printed in London in 1 784. I tranfmit you a copy of as 



much 



