a Thunder-JIorm in Scotland. 65 
a&ed ftrongly upon the wheels; and, on examination, I found 
evident marks of fufion on each of them, which I now {hewed 
to many people who had aflembled around us. The furface of 
the iron, to the length of about three inches, and the whole 
breadth of the wheel, had become of a bluifti colour, had 
entirely loft its polifh and fmoothnefs, and had the appearance 
of drops incompletely formed on its furface ; thefe were of a 
roundifh form, and had a fenftble projection. I fufpected that 
the great heat, which had been communicated to the iron, might 
probably have burnt the wood of the wheels; but this I did 
not find to be the cafe. To afcertain whether thefe marks 
were occafioned by the explofion which had torn up the ground, 
we pufhed back the cart on the fame tracks which it had de- 
fcribed on the road; and found, that the marks of fufion an- 
swered exactly to the center of each of the holes; and that, at 
the inftant of the explofion, the iron of the wheels had been 
lunk deep in the duft. They had made almoft half a revolu- 
tion after the explofion, which might be occafioned by the 
falling down of the horfes, which pulled the cart a little for- 
ward. On examining the oppofite part of the wheels, or that 
part which was at the greateft diftance from the earth, no mark 
of any kind was obfervable. The broken earth ftill emitted a 
ftmell fomething like that of ether. The ground was remarka- 
bly dry, and of a gravelly foil. 
It would appear, that this great explofion had, in an inftant, 
pervaded every fubftance connected with the cart, the wheels of 
which had probably conducted it from the ground. They had 
been completely whetted but a few minutes before, as well as 
the legs and bellies of the horfes, and this might, perhaps, be 
the reafon why the hair on thefe parts was much more burnt 
than on the reft of their bodies. However, the two horfes 
Vol. LXXV1I. K had 
