132 Blasting of Rocks—Danger and Remedies. 
igneous action at Etna and Vesuvius, and in the Lipari or Eolian Is- 
lands; and occupied as he is in this very paper with the discussion 
of the subject. Under the trap described by Lt. Col. Imrie, there 
are several stratified rocks, among which are sandstone, limestone, 
and bituminous shale ; and the sandstone is the stratum upon which 
the trap immediately reposes, and it alternates more than once with 
the other rocks, but it is not described as being at all altered in the 
vicinity of, or contact with the trap. Prof. J. W. Webster, in the 
first volume of this Journal, has well described similar facts, at the 
Calton Hill, in Edinburgh; a place with which I was myself familiar. 
These remarks have been extended far beyond my original design, 
and I will conclude them, by again calling the attention of geologists, 
and of all intelligent observers; in the first place, to the delineated 
section which illustrates these remarks ; and in the next place, to the 
scene itself, which is well worth the trouble of an excursion from 
Hartford, and which, notwithstanding the interest so properly excited 
by its fine institutions, and surrounding country, and by the grati- 
fving exhibition of a flourishing and beautiful city, should hereafter 
stand preeminent among the Lions of this region, and be visited by 
all travellers, who are admirers of rich and noble landscape, or of 
astonishing geological facts. 
Arr. XIV.— Danger from the premature explosion of gunpowder 
an the blasting of rocks, with suggestions as to the means of pre- 
vention. 
Tue deep interest excited by the following letter, induced me to 
submit the subject to the consideration of a gentleman whom I knew 
to have had considerable experience in blasting rocks, and in whose 
science and skill, I have the greatest confidence. As he has favored 
me with an answer, which contains very important suggestions, I am 
happy to lay it before the public, in connexion with the letter of Dr- 
Catlin. I have added also, some suggestions of my own.—Ed. 
I. Letter of Dr. Catlin. 
Haddam, Con. August 25, 1829. 
TO PROF, SILLIMAN, 
Dear Sir—Being desirous to promote the welfare of my fellow- 
cael and to render the situation of those engaged in a hazardous 
nent, as safe as the nature of the case will admit, I take the 
