204 On the Rotary and Orbicular 
formation of one of them:—or, as the consequence of a subse- 
quent chemical decomposition of one of the surfaces in contact : 
—that I cannot doubt, if it could so occur, that Mr. W. or any 
others of similar ways of thinking on this point, could conduct 
me to the very strongest case in Great Britain, of their alleged 
charring or changing of adjacent substances, by the heat of Ba- 
salt: I could point out facts on the spot, which would completely 
overturn such a supposition ;—with hand Specimens, theoretically 
selected, or with descriptions by others, so tinctured, the result 
might possibly be otherwise. This test, our theoretic inferences 
must bear, in every instance, if they are worth anything, or 
worthy of being communicated to others, or remembered. 
I have already and fully explained myself, in p. 253 of your 
last volume and elsewhere, as to the locally variable thicknesses, 
of continuous strata of Basalt, forming what may be considered 
as somewhat irregular lenticular masses, either plano- or double 
convex; surely Mr. W. will on reconsideration agree with me 
in thinking, that “ wedge-shaped masses,” but inaptly desig- 
nates them. I hope that none of your succeeding Numbers, for 
some time, will appear without communications from Mr. Winch, 
Mr. Forster, Mr. Fryer, or some other industrious Observers of 
the Geological facts, of the northern English Counties, disposed 
to freely communicate what they know. 
2d P. S.—I heartily wish that Mr. Winch, or his Friend to 
whom he alludes in your last, would send up to Mr. Sowerby 
(No. 2, Mead-place, Lambeth) ample Specimens of all the kinds 
of Shells, found in the Limestone of Wratcliff, or in any other 
Quarries, with their precise localities marked; in order that in 
future Numbers of his ‘* Mineral Conchology,” they may be 
drawn, described, named and compared, with other distant lo- 
calities of the same species of Shells. A. Cols 
XXX. On the Rotary and Orlicular Motions of the Earth. By 
‘ Mr.H. Russet. 
To Mr. Tilloch. 
Sir, — I WILL esteem it a favour if you will give a place to the 
following letter, in your publication,—and am, &c. 
Norwich, July 24, 1817. Henry RussEL. 
no . 
“ To Sir Richard Phillips. 
« S1rk,—To account for the attraction of gravitation, has long 
been an object of my most serious inquiry, and | am sorry I can- 
not find in your paper (of last June) that gratification which by 
the 
