886 Opinions upon Clay Stones and Concretions, [September 
by a molecular displacement, the particles of the concreting sub- 
stance being gathered together by some action similar to electri- 
cal action. The paper elicited from M. Becquerel assent in the 
following words: “ A mass of geological facts adequately show 
that there has been and is yet, in different rocks, centers of action 
around which foreign substances and their compounds gather. 
There is no doubt that these transferences of molecules may have 
been effected by forces analogous to electricity, but it is not suffi- 
cient to suppose that the phenomenon has an electrical origin, it 
is necessary to prove it; this is what I have already done ina 
certain number of cases by reproducing these compounds,” &c. 
M. Virlet, in the same paper, compiles a chronological state- 
ment of the views held by geologists and chemists previous to 
his own publication, from which the following notes are taken. — 
In 1816 Mr. Buckland speaking of nodular siliceous beds and 
the flints of chalk, says they seem to have been formed whilst 
the material which encases them was yet soft, and to have reached 
their hard or solid condition almost contemporaneously. The 
separation of the silica from the calcareous mass would have 
been achieved through the attractive forces which drew the 
siliceous particles towards certain centers. In 1834 M. de La 
Beche remarks, “that we see in the rocks of mechanical origin 
certain very remarkable aggregations which must have heen Be 
duced by the mutual attraction of the molecules which com- 
pose them.” He remarks that these nodules contain mort cat: 
bonate of lime than the marls and argillaceous schists whi S 
round them, and in allusion to their laminated chanos g 
“that we can scarcely doubt that they have been formerly the 
continuation, one of the others. The molecules of pae 
matter have separated themselves from the marls to ey yi | 
now see them, and we would not probably be mistaken igre 
we assumed that the beds of the particular deposit, aie pi 
taining sufficient carbonate of lime to form SuCCeROIES ed in the 
tain nevertheless too much of it to remain dissemina} | 
marls without being gathered into small masses. ee 
Mr. Babbage showed that siliceous particles form woe” 
ary-like bodies in the clay preparations used in the n 3 
of porcelain, M. Virlet objects to the finding of any é 
the two cases, as the pottery mass has been for 
the natural beds have been deposited slowly ove 
med at once ant 
r long periods. ce 
