On Electricity. 261 
P. 68, 1. 17, in clay-pits +:—* These alluvial Marl-pits with 
Granite and other foreign Bolders, extend into the 
NW corner of Derbyshire, Rep. i. 456. 
69, 1. 22, denominated rents*.—* Mr. B. seems here 
alluding, to the nearly vertical joznts, slines cutters, 
&c. between blocks of stone, or masses of Coal, 
&c. which are generally peculiar or confined to 
each bed; and should not therefore have been 
confounded by a common term, with the vastly 
different phenomenon of Faults, as is done in 
page 47, see my Note on page 162. 
72, 1. 3, to mica slate *,—* Did not Mr. B, note, in his 
Woburn ebservations, that the micaceous stones 
alluded to, were worn and decomposing pebbles 
among the Gravel?. I have found such, very 
plentifully, on the lower chalk hills NE of Dun- 
stable, and they have also reached Derbyshire, 
with many of their travelled companions, see 
Rep. i. 466. . 
73,1. 10, of statuary marble *.—* Mr. John Lingard, 
the occupier of Lodge Farm in Great-rocks Dale in 
Derbyshire, showed me small specimens of white 
granular Marble, scarcely if at all distinguishable 
from foreign statuary, which came I believe from 
a Dyke or vein of this stone, which there inter- 
sects the 4th Limestone Rock, Rep. i. 414. 
83,1. 9, secondary rocks (6)*.—* In a note on page 
45, I have already expressed a doubt, on the reality 
of such strata as are represented, No, 6, in fig. 1, 
plate I. and shall feel obliged to Mr. B. if he will 
particularly point out as many undoubted cases 
of the kind, as he can. 
My next communication commences Mr, B’s 4th Chap- 
ter, and shall be sent in due time. 
I am, sir, 
Your obedient servant, 
Upper Crown-street, Westminster, Joun FarRey Sen. 
26th July, 1813, 
XLIV. On Electricity. By Mr. Georce JoHn SINGER, 
Lecturer on Chemical and Experimental Philosophy. 
Tue phenomena observed in an experiment detailed in 
the last number of this Magazine*, as indicatiye of a double 
* Page 161. 
R3 current 
