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XXIII. Meteorological Ohservalions on a Thuvder Stormy 

 with some Reinarks on Medical Electricity. By Mr, 

 Cornelius Varlev, 



To Mr. Tilloch. 



Sib, X TAKE the liberty of sending you a description of a 

 distant thunder storm*, the electrical phsenomcnaof which 

 were so distinctly visible as to leave no doubt on my mind 

 oF the exclusive agency of one electric fluid. (See Plate VI). 



Observing it to lighten one eveninii Trequently without 

 hearing thunder, I went into the fields, and, looking north- 

 ward, saw the horizon lined with clouds, there being none 

 over head except a few very small ones proceeding in that 

 direction. These were upon a level with the lower cloud; 

 tor they joined it afterward — a circumstance which serves to 

 prove that a diminution was taking place in the voliime of 

 the atmosphere, for otherwise they could not have overtaken 

 the storm, being at first too far ofi" to be afiected by any 

 electrical attraction. At the commencement of the storm it 

 lightened in various parts of the clouds, butmore frequently 

 in one place. Soon after this the clouds seemed united in 

 one, and the place of the lightning became stationary, 

 (where in the drawing the light cloud is placed.) and here 

 commenced the effect w hich seenitd distinctly to show in 

 what manner the electric fluid is conducted from the upper 

 regions to the earth. 



At first a small round cloud (about an eighth part of that 

 represented) appeared behind the lotvr dark cload, and partly 

 seen above it. In this cloud it frequently lightened; and 

 just after the light was extinguished,' the electric sparks 

 struck to the earth from the under surface of the lom black 

 cloud. This double transniission was manv times repeated, 

 till at length the lower cloud ceased to give spa. ks to the 

 earth at the spot immediately under the higher cloud. thou2:;h 

 it was still frequently receiving them from it. I then found, 

 by casting my eye along the lower cloud, that every charge 

 from the upper one travelled about four miles westward 

 along the lower cloud, and then darted to the earth. I 

 knew it travelled in this manner by frequentlv seeing it jump 

 over one and sonietinies over two chasms in the lower cloud 

 in its passage to the western end. The time it took lo travel 

 the length above mentioned, was while I could count 20 or 

 30 — but twice I counted 60 before it struck the earth. 



• This is commonly called summer lightning, i. e. there is fine weather 

 over head, and the ligiitning is so tar off that the thunder cannot be heard. 



Vol. 34. No. 137. i^c/v^ IfaOP. L During 



