1884.] On the Evidence that the Earth's Interior is Solid. $93 
mathematical laws. It is incumbent on the physicist to explain 
earthquake motion, the sinking and rising of different portions of 
the earth's crust, volcanic phenomena, the uniformity in composi- 
tion of lavas, the structure of volcanic rocks, sedimentation, fault- 
ing, vein formation, etc., etc., by his theory of a solid globe. 
Geological facts are just as positive as physical ones, and it is as 
necessary for the physicist to reconstruct his theory of a solid 
tarth to suit geological facts, as it is for geologists to reconstruct 
their theories to suit the so-called physical demonstrations of a 
solid earth—demonstrations that merely show that under the as- 
sumed conditions and hypotheses the physicist’s imaginary globe 
must be a solid one. 
Are not speculations, speculations still, even if threaded to- 
gether by a long series of mathematical formule, and are not all 
led mathematical proofs of the earth’s solidity the mere 
Working out of certain assumptions? Huxley was indeed right 
when he said, as the present writer would like to say: “I do not 
Presume to throw the slightest doubt upon the accuracy of any 
of the calculations made by such distinguished mathematicians as 
l who have made the suggestions I have cited, * * * but 
I desire to point out that this seems to be one of the many cases 
| in which the admitted accuracy of mathematical processes is al- 
-to throw a wholly inadmissible appearance of authority 
over the results obtained by them. Mathematics may be com- 
' Pared to a mill of exquisite workmanship, which grinds you stuff 
any degree of fineness; but, nevertheless, what you get de- 
| Ee on what you put in; and as the grandest mill in the world 
ten a extract wheat-flour from peascods, so pages of formulz 
| get a definite result out of loose data.” 
ae aly in mathematical and physical science, but in all sci- 
7 » 20 amount of discussion can give the conclusion any greater 
; ee the premises have, but attracted by the conclusion 
s ere thi in of argument, the data are apt to be overlooked. 
IS not the case many a structure, reared with great care 
: Sigal as established, would be found to rest on flimsy 
oo as the mathematical and astronomical determina- 
. 3 earth’s solidity are concerned, it would seem that 
“co Exists as to the correctness of the premises as applied 
Sarth, and hence like doubt regarding the conclusions. 
l address, Geol, Soc. London, 1869, p. 1. 
