142 
It has often been remarked that that which has been un- 
questioned, need not be unquestionable. But let us take an 
example : — Suppose that we placed a cold 681b. shot in front 
of a fire, and caused this shot to rotate for about half-an-hour, 
we should then have the surface the hotest part, whilst the 
centre would be quite cold. Then suppose that we removed 
this shot from the fire, and swung it about in a cold air, 
the surface would then get cold before the lower portion, 
in consequence of the radiation of the heat. Thus if we 
were to examine the metal at a short distance from the 
surface, this metal would increase in heat up to a certain 
distance, but it would again decrease, until it became quite 
cold near the centre. 
What then should we consider the value of the conclusion, 
which at once affirmed that because the heat increased from 
the surface of this shot to one-tenth of an inch from the 
surface, that therefore the centre of the shot must be red hot. 
Most surely this would be too hasty a theory. Yet this 
is the only evidence which leads to the conviction that 
the centre of the earth is in a state of fusion from heat. 
Heat will explain much in geology, but it must not be a 
heat in the centre of the globe, nor can a cooling globe 
explain any of the geological facts, for contraction follows 
cooling, and direct evidence speaks to expansions only. 
A powerful telescope being directed to the planet Yenus 
enables us to perceive that some very singular conditions pre- 
vail upon her. She is spherical like the earth, she rotates on 
her axis, she revolves around the sun, she has an atmosphere, 
and, in fact, appears very like our globe, except that a 
singular annual variation of climate prevails upon her 
surface. If Great Britain were transferred to the same 
latitude on Yenus that it occupies on our earth, we should 
have an arctic climate in winter, during which the 6un would 
be absent nearly 40 days, and thus Scotland, Wales, and 
