72 
THE CABINET OF NATURAL HISTORY 
have not taken the pains of making the experiment; 
although sufficiently apparent from its hardness, &c. 
I enclose the article in the Journal, to which I have 
alluded, and will forward the specimen with this, the first 
convenient opportunity. 
Very respectfully, your obd’t servant, 
A. W. FOSTER. 
The following is attached to the specimen now in the 
Philadelphia Museum: — “ Petrifaction of Wood. — This 
piece of petrified wood, was broken from the stump of a 
tree measuring fifteen feet in circumference, and about four 
feet in height, by actual measurement. It was found on 
the S. W. bank of the Missouri River, about thirty miles 
below the mouth of the Yellow Stone, and nearly opposite 
the junction of White Earth River with the Missouri, in 
lat. about 48° 15',” 
The most remarkable facts, concerning the petrfaci- 
tions of this region, are, that stumps, limbs and roots 
of trees of all sizes, broken into fragments, lie scattered 
over the country for a distance of thirty or forty miles, at 
an elevation above the level of the river, of at least five 
hundred feet, and at a point which is computed at six or 
seven thousand feet above the level of the Ocean. 
Surgeon Gale, of the Army, who, as well as myself, 
was attached to the military expedition that ascended the 
Missouri in 1825, from Council Bluffs to Two Thousand 
Mile Creek, and who accompanied me on an exploring 
and hunting excursion, across the country, from below the 
mouth of White Earth River, to the Yellow Stone, as- 
sisted in examining and measuring the stumps of some of 
those petrified trees, and he gave it as his opinion, that 
from the appearance of the country, some thousand years 
must have elapsed since a thick forest of timber stood 
where now nothing remains but these petrified fragments 
He was rather inclined to the opinion, that the kind of 
wood, was the cotton wood of the Missouri country, com- 
mon enough along the banks of the Missouri river and its 
tributaries. 
This subject furnishes abundant matter for the natural 
philosopher, for whose curiosity and speculation it is here 
submitted. G. H. CROSMAN, 
U. S. Army. 
DEFENCE OF THE PERCUSSION. 
The general opinion is, that shot is propelled to a greater 
distance and with more uniform velocity from a gun, in 
proportion as the force of powder exceeds the weight of 
shot; and it is upon this false supposition that the anti-per- 
cussionists have grounded their objections to detonating 
guns, by affirming, that “the explosion takes place so in- 
stantaneously that the whole of the load of powder is not 
ignited, and that a portion is driven out unexploded.” 
It is well known that the resistance which bodies meet 
with in passing through a fluid, increases as the square of 
their velocity. Therefore a load of shot, passing through 
the air at a given rate, would meet with four times the re- 
sistance if its speed were doubled. Hence, if one drachm 
of powder will carry a load of shot forty yards with a given 
force, the power of two drachms would, it is true, give a 
double velocity to the shot at its egress from the muzzle of 
the gun; but the resistance being now four times greater 
than in the former instance, the force of it at the distance 
of forty yards would be very much diminished. 
I have shot three seasons with my present gun, which is 
a double-barrelled detonator. For the two first seasons I 
used the proportions for the load which I received from 
the gunmaker, and during that time I do not recollect to 
have killed a bird farther than forty paces. Thinking this 
might be improved upon, I determined to try the effect of 
reducing the quantity of powder; and having first loaded 
with the original charge (and No. 5 shot), I fired at a tin 
powder flask at the distance of forty measured yards, and 
struck it with five shots, but the marks were barely per- 
ceptible. I then reduced the quantity of powder (only) 
one quarter, and the shots made much deeper indentations 
in the tin than before. I then reduced the powder still 
further, to about two-thirds of the original charge, and the 
result answered my expectations fully: for I found five 
shots as firmly set in the tin as stone was ever set in gold. 
I measured the distance of two shots at birds: one was 
sixty-two paces, and the other sixty-three; in both instances 
the birds fell dead at the fire. 
I have from the first maintained that a detonator ignites 
more grains of powder than a flint and steel gun does. 
The result of my experiment has fully established my opin- 
ion upon this point. The fire from the copper cap being 
driven with considerable force into the load of powder, ig- 
nites the whole; the force of which explosion being too 
great for the weight of shot, diminishes at a certain distance 
the velocity of the latter. 
On the other hand, the fire communicates with the pow- 
der in the barrel of a flint and steel gun merely by the igni- 
tion of grain by grain; so that just as much of the powder, 
and no more, explodes as is sufficient to discharge the load. 
A proper regulation of the charge, therefore, seems alone 
requisite to make a detonator carry as strong as a flint and 
steel gun; and if the means for diminishing the force of 
the powder instead of increasing it, had been consulted, 
less time would have produced a more satisfactory result. 
Sporting Magazine. 
