248 On the variable Action of the Electric Column. 



ths adjoining fields, where I saw large slabs of them lying upon 

 the surface, havuig been turned up by the plough. The culti- 

 vated state of the country prevented further examination : others 

 vise I have little doubt that the compact felspar would be found 

 in sUit, for the masses here were in nothing different as to com- 

 position from the blocks at Staunton Drew, 

 . Oromiic Rerjiains. After the very elaborate manner in which 

 Mr. Townscnd has treated this sul^ject, I should only be repeat- 

 ing his observations were I to attempt to add anv thing. There 

 is, ho\vever, one curious fact which I believe, he has failed to 

 •mention. It is, that although we find the fossilized remains of 

 the encrlniis so extensively distributed in the mountain lime- 

 etone, and a prodigious abundance of shells chiefly anomice and 

 pectens ; yet in the indurated sandstone lying upon, and the other 

 formations below the limestone, this sort of petrifactions, as far 

 as I can observe, does not appear. I had once or twice seen in 

 cabinets at Bristol, specimens of a fine-grained friable red sand- 

 stone a])Ounding in delicate impressions of a spinous anomia, 

 and I was quite at a loss to know v/here this substance occurred, 

 till I found it under York Place, ajiparently filling fissures in th.e 

 indurated sandstone. A friend of mine the other day sent me 

 a specimen of indurated sandstone containing the impression of 

 the bark of a pine, which is the only instance of that kind of 

 stone (as far as I know) containing in its substance any thing 

 like an organic remain. 



XL. On the variable Action of the Electric Colinnn. 

 By Mr. J. A. Deluc. 



To Mr. Tilloch. 



Sir,-- X OUR number for June last contains a paper of Mr, 

 Ronalds's, which could not but interest me, as it relates to the 

 variable action of the electric column. This varia!)]eness de- 

 pends on ia3,ny causes, with respect to one of which we do not 

 agret , and it will be ;he object of this paper. 



I have 'ound in my experiments, that an increase of moisture 

 did increase the action of the column. Mr. Ronalds is of a dif- 

 ferent opinion ; but as he describes the experiments from which 

 he conclude that moistiire has a very little effect on that ac- 

 iiun, it will he easy for me to show that this disagreement be- 

 tween us results from a mistake on his part, and that his cxperi- 

 mf nts, though very ingenious, according to his idea of the sub- 

 ject, are quite dissimilar to those whence I had derived my con- 

 clusion . 



One 



