" Spheroidal Theory'' of the Inferior of the Eartli. 139 
and contracting crust grasping with ever-increasing force 
the internal molten mass, until the tenacity of its materials 
could no longer resist the tremendous reaction. Then would 
a disruption ensue, and vast quantities of igneous matter be 
ejected from the yawning fissures. The lips of the chasms 
would then re-approach and finally press powerfully against 
each other, producing the phenomena of anticlinal and 
synclinal foldings so familiar to the geologist. Again, in 
the gradually up-heaving force generated by the accelerated 
diurnal motion of the crust, in consequence of its contrac- 
tion through refrigeration, is seen the cause of those re- 
peated risings and subsidences which have been going on in 
all geological periods, from the most remote down to the 
present. In the changes so effected in the relative distri- 
bution of sea and land, we recognise one of the most influen- 
tial climatic agencies, by means of which the temperature due 
to the position of a place in latitude is powerfully modified. 
Connected also with the distribution of sea and land is that of 
terrestrial magnetism, as is at once apparent from a com- 
parison of a map of isothermal with one of isodynamical 
magnetic curves. So closely related, in short, are all the 
parts of the great system of nature, that a discovery in one 
department becomes a key to the solution of difiiculties in 
others. Geologists are deeply indebted to the physical 
sciences for the powerful aid which these have furnished 
them in their investigations, and the physical sciences have 
already to a small extent been, and will undoubtedly in a 
great degree be, benefited by the researches of geologists. 
On the motion of the President, the thanks of the Society 
were given to Mr Stevenson for his communication. 
II. RemarJcs on Br Macadam's " Spheroidal Theory"" of the Interior 
of the Earth. By T. Strethill Wright, M.D. 
Dr Wright commenced his paper by an enumeration of 
various circumstances under which fluids assumed the so- 
called " spheroidal" state, and explained the meaning of the 
VOL. Ill, T 
