134 Scientific Intelligence. 
being 141, when a year is taken as the unit of time, and a British 
foot the unit of space, the radius of the hemispherical surface of 
maximum temperature is therefore 16°8X«/t te hus at the 
end of one year it is 16°8 feet, at the end of 10 at years it is peer 
feet, from the origin 
(8) At any point at a finite niemnee sai the solid (which, by 
hypothesis, is at temperature zero at the instant when the fire is 
where the fire was applied, is [pz, or, according to the value 
t2 
found for trap rock, 337, of a year. Thus it appears that at one 
French foot from the place of the fire, the maximum temperature 
is acquired a day and a half (more exactly 1°54 days) after the 
PB ahi and removal of the fire. At 15:4 French feet from 
the fire, the maximum temperature is reached just a year from the 
beginning and at 1540 feet the maximum is reached in 10,000 
ears 
made by Dr. Schwartz in the mining district of pBronsint xx i 
th 
inciiaee of 38°°3 C, in 1587 m., which is at the rate of 1° C. in 
41-4 m., or 1° F. in 75°5 feet 
The comparison of she deepest observations with the shallowest 
which was undertaken as a check upon the above, gave a mean 0 of 
1° F. in he ne 
halen bored upw e of ten feet ‘ae some 0 
deepest seams. The vherioeunser used i > — terized as a pone 
action one—not a self-registe: one— slg placed in the! bot- 
