, 
On Safe-Lamps for Mines, 117 
day, and to have become extinct long before the surface of the 
earth became fitted for the reception of man, or even of the 
quadrupeds which are subservient to his use, and which would 
seem to have immediately preceded his appearance, since we 
find their relics only in alluvial grounds. 
With respect to the successive extinction of these races of ani- 
mals, it is a fact easily explained. As the water of the ocean 
became prepared for more perfect creatures, it may be supposed 
that it was unfit for sustaining those to which its tormer~quali- 
ties had given birth. 1 have elsewhere endeavoured to show 
that all land animals had eriginally a local and determinate seat 
on the globe. Confined by natural barriers within the limits of 
their native regions, many of them seem to have awaited the 
hour of their destruction by means of inundations and ether ca- 
tastrophes. 
On the hypothesis proposed by your correspondent, I shall 
only remark that, although purely conjectural, it is liable to an 
objection drawn from physical considerations. A number of 
curious coincidences render it highly probable that the orbital 
motions of the planets and their motions of rotation were pro- 
duced by the same physical cause, and were therefore simulta- 
neous in their commencement. The circumstances I allude to 
are set forth in a most luminous and striking manner by Laplace 
in his Systéme de la Nature. But it is futile to enter into a 
discussion of what may have happened before the creation of the 
sun. 
Having thus fully stated the grounds of the opinion I formerly 
ventured to offer, I shall decline all further controversy on this 
subject, 
I have the honour to be, sir, 
Your obedient servant, 
Bristol, Feb. 12, 1816. J.C. PricHarp, 
XXV. On Safe-Lamps for Mines. 
To Mr. Tilloch. 
Sir, — . the month of November last I had the pleasure to 
communicate to you the result of several successful experiments, 
made in the presence of the Literary and Philosophical Society 
here, with the safe-lamp invented by Mr. Stephenson, which, I] am 
happy to add, has been since used in the most dangerous parts of 
some coal-mines without any accident having occurred. On Tues~ 
day the 6th instant Sir H. Davy’s recently improved lamp, the 
flame of which is encompassed by wire-gauze, was also exhibited 
by 
