HOLWELL CAVERN. 123: 
Appendir to Paper on Bulwell Enmern. 
PAGE 14. 
Being desirous to try how far the transfer of carbonate 
of lime, from a piece of limestone upon a piece of clay-slate, 
under electric action, would succeed,—that is, whether the 
carbonate of lime so transferred, would appear in the 
form of common carbonate of lime upon the clay-slate, or 
of arragonite,—I made the following experiment. I placed 
a large glass funnel vertically in a wooden stand, filling it 
about one-fourth with a mixture of limestone and clay- 
slate coarsely powdered, and then pouring in water up to 
the brim. Underneath this I suspended a piece of clay- 
slate, some inches in length, on the middle of which the 
water from the funnel above was constantly dropping, 
keeping the greater portion of the suspended clay-slate 
continually wet. On one end of this wet slate I caused 
a piece of limestone to rest, connecting it by a platinum 
wire with the positive pole of a small and weak, but con- 
stant, voltaic battery. On the opposite end of the wet 
clay-slate, I caused another, but smaller piece of clay-slate 
to rest, connected by a platinum wire with the negative 
pole of the same battery. The electric action gradually 
drawing to the positive limestone a portion of the very 
minute quantity of mineral acid common to almost all 
waters not distilled, extracted slowly a part of the lime, 
which on well known principles was carried to the negative 
clay-slate, and is now depositing itself in the form of, no£ 
Q3 
