124 G U N P O 
fire, and was projefted into the atmofphere by the elaf- 
tic fluid generated in its own combuftion, leaving a very 
beautiful train of light behind it, and difappearing all 
at once like a falling ftar. This amufing experiment 
was repeated very often, and with globes of different 
fizes. When very fmall ones were ufed fingly, they 
were commonly confumed entirely before they came 
out of the barrel'of the piftol; but when feveral of 
them were ufed together, fome, df not all of them, 
.were commonly projedted into the atmofphere on fire. 
As this imperfedl combuftion of the gunpowder feems 
to be the caufe which has hitherto prevented its almoft 
incredible force from being more accurately afcertained ; 
the count deduces, as an evident confequence, that the 
readied: way to increafe its effedls, is to contrive mat¬ 
ters fo as to accelerate its inflammation^ This may be 
done in various ways; but, in his opinion, the moft 
fimple and moft effectual manner of doing it would be 
to fet fire to the charge of powder, by fhooting (through 
a fmall opening) the flame of a fmaller charge into the 
midft of it. He contrived an inftrument on this prin¬ 
ciple for firing cannon ; and it was found, on repeated 
trials, to be ufeful, convenient in prattice, and not lia¬ 
ble to accidents. It like wife fuperfedes the neceflity 
of ufing priming, of vent-tubes, port-fires, and matches; 
and on that account he imagines it might be made ufe¬ 
ful in the Britifh navy.—For other experiments on the 
explofive force of gunpowder, fee the article Che¬ 
mistry, vol.iv. p.237-38. 
It has been obferved by M.Humboldt, in the Journal 
des Sciences et des Arts, that the effects of gunpowder, in 
mines, &c. have been found to be very much increafed 
by leaving a confiderable fpace between the powder and 
the wadding. He fays, that the perfon who made this 
difcovery was led to it by the confideration of a fadt 
well known, but which cannot be too carefully guarded 
againft, namely, that a mufket, or fowling-piece, is 
very apt to burft, if the wadding is not rammed down 
xlofe to the powder. Hence it is obvious, that in load¬ 
ing a fcrew-barrel piftol, care fhould be taken that the 
cavity for the powder be entirely filled with it, fo as to 
leave no fpace between the powder and the ball. With¬ 
out undertaking to fhew how far thefe two circum- 
ftances are analogous to each other, we think it proper 
to mention twb other fadts of a nature fimilar to the 
above. 1. If a bomb or fhell is only half filled with 
gunpowder, it breaks into a great number of pieces; 
whereas, if it is quite filled, it merely feparates into 
two or three pieces, which are thrown to a great dif- 
tance. 2. If the trunk of a tree is charged with gun¬ 
powder, for the purpofe of fplitting it, and the wad¬ 
ding is rammed clofe down upon the powder, in that 
cafe the wadding is only driven out, and the tree re¬ 
mains entire; but if, inftead of ramming the wadding 
clofe, a certain fpace is left between the powder and 
the wadding, the effedts of the powder are then fuffici- 
ently violent to tear the tree afunder. 
It has alfo been difcovered, (hat levigated lime ufed 
with gunpowder, is of infinite advantage in rending 
rocks, ftones, &c. This difcovery was made by H. D. 
Griffiths, efq. of Caerhun near Conway, in North 
Wales ; and which we Ihall ftate in his own words : . 
“In clearing my lands of the heaps of ftones with 
which this country every where abounds, I found the 
quantity of gunpowder ufed in the operation to amount 
to a confiderable fum at the end of the year ; and, as the 
price of this article has of late been increafing to an enor¬ 
mous amount, I had recourfe to an expedient, by which' 
the expence of it has been materially diminillied. I 
weighed out two pounds of gunpowder, and one pound of 
quick-lime, well dried and pulverifed; which, after hav¬ 
ing been thoroughly mixed with each other, I delivered 
to the blafter, with directions to apply it, in fimilar quan¬ 
tities as he would have done the gunpowder by itfelf. I 
then feleCted fix of the hardeft granites I could find for 
W D E R. 
the experiment; and the effeCts of the explofion were 
recifely the fame as if gunpowder alone had been ufed. 
t now occurred to me, that this might be fallacious, 
and that a fmaller proportion of gunpowder would pro¬ 
duce the fame effeCt as a larger ; I accordingly ordered 
the man to bore holes in a.fimilar number of ftones, of 
the fame texture and fize with the former, and to put 
in a lefs quantity of gunpowder, by one-third, than he 
would have done if it had been left to his own manage¬ 
ment. The ftones were feparated by the fhock ;-but 
the difference in the effeCt was manifeft to every perfon 
in the field : thofe with the mixture of lime and gun¬ 
powder having been much more effectually broken and 
fhattered than the others. After the fuccefs of this 
experiment, I have conftantly adhered to the practice ; 
and am fo fatisfied of its utility, that I wifh to fee it 
generally adopted. One thing’ is certain, that a mix¬ 
ture compofed of equal parts of quick-lime and gun¬ 
powder, will explode ; and, if this mixtre were ufed 
merely as a train of communication to the powder with¬ 
in the ftone, what a vaft faving would it be in works car¬ 
ried on upon an exterifive fcale, fuch as the numerous 
quarries and mine-works of this kingdom!” 
METHOD of PROVINGjGUNPOWDER. 
There are feveral methods of examining gunpowder; 
fome with regard to its purity, others with regard to its 
ftrength. Its purity is known by laying two or three 
little heaps near each other upon white paper, and firing 
one of them. For if this takes fire readily, and the 
fmoke fifes upright, without leaving any drofs or fecu¬ 
lent matter behind, and without burning the paper, or 
firing the other heaps, it is efteemed a fign that the ful- 
phur and nitre were well purified, that the coal was 
good, and that the three ingredients were thoroughly 
incorporated together: but, if the other heaps alfo 
take fire at the fame time, it is prefumed, that either 
common fait was mixed with the nitre, or that the coal 
was not well ground, or the whole mafs not well beat 
and mixed together ; and, if either the nitre or fulphur 
be not well purified, the paper will be foul or fpotted. 
Several inftruments have been invented to afcertain 
the Jlrengtk of gunpowder, fuch as powder-triers afting 
by a fpring, commonly fold at the (hops; and others 
again that move a great weight, throwing it upwards, 
which is, however, an eprouvette not to be depended 
upon. Thefe machines, fays Mr. Robins, though more 
perfeCl: than the common powder-triers, are yet liable 
to great irregularities ; for as they are all moved by 
the inftantaneous ftroke of the flame, and not by its 
continual preflure, they can never determine the force 
of the fired powder with fufficient certainty. Another 
method is to judge from the range given to a large folid 
ball, thrown from a very fhort mortar, charged with a 
fmall quantity of powder ; which is alfo an uncertain 
way, both on account of the great difproportion be¬ 
tween the weight of the ball and powder, and the un¬ 
equal refiftance of the air; not to mention that it is too 
tedious to prove large quantities of powder; for, if 
each barrel of powder was to be proved in this manner, 
the trouble of charging the mortar, and bringing back 
the ball each time, would prove an endlefs bufinefs; 
and if a number of barrels were to be received on the 
merit of a few, it is very probable that fome bad ones 
would occur amongft them, which may prove a great 
injury to the fervice in time of aCtion. Thefe excep¬ 
tions do “no ways hold (fays Mr. Robins) againft the 
method by which I have tried the comparative ftrength 
of different kinds of powder, which has been by the 
aftual velocity given to a ball by fuch a quantity of 
powder as is ufually efteemed a proper charge for the 
piece : and as this velocity, however great, is eafily 
difcovered by the motion which the pendulum acquires 
from the ftroke of the ball, it might feem a good 
amendment to the method ufed by the French, (viz. 
4 that 
