( 440 ) 



Some Observations on Atmospheric Electricity. By John Davy, 

 M. D., F. R. S. Communicated by Professor Forbes. 



{Read 4<th January 1 836.) 



The few facts we possess relative to the chemical agency of 

 atmospheric electricity, and a certain degree of obscurity con- 

 nected with these facts, as pointed out by Mr Faraday,* in com- 

 menting on the late Mr Barry's results, published in the Phi- 

 losophical Transactions for 1831,f have induced me to institute 

 some experiments on the subject, with the hope of acquiring ad- 

 ditional information. 



Reflecting on the manner in which, in certain instances, the 

 great experiment of Franklin, in apparent proof of the identi- 

 ty of common and of atmospheric electricity, had been repeated, 

 especially in our own country ;i reflecting also on the experi- 

 ments of M. Colladon on atmospheric electricity,§ made by 

 means of a lightning-conductor, — it appeared to me not impro- 

 bable that results might be witnessed of some interest by substi- 

 tuting for an electrical kite, the means employed by Mr Barry, 

 an insulated wire raised a few feet above the summit of any 

 building of moderate height. 



As most convenient for the trial, I chose a turret just fifty 

 feet above the street, the highest part of my own house — situa- 

 ted rather high — though not in the loftiest part of Valletta, and 

 overtopped considerably by the summits of several of the public 

 buildings of the city. There I elevated, by means of an iron rod 



* Philosophical Transactions, 1833, p. 42. 



t On the Chemical Action of Atmospheric Electricity, by Alexander Barry, Esq. 

 F. L. S. 



X Phil. Trans, abridged, vol. x. p. 303. 



§ Annales de Chimie et de Physique, tome xxx. p. 72. 



