phenomenon explained by the fact that
the 20 mm. thick wall of the shell re-
moves the charge that far from the ob-
ject. We call attention to the fact that
we speak of the direct action on the ob-
ject ; total effect, acting also at a dis-
tance, must be distinguished therefrom ;
in the latter such small distances as 20
mm. can have no effect. This distinction
also accounts for the fact that, in all ex-
periments in which the force can act only
in one direction on an object in direct
contact, only relatively correct results are
obtained, and that our experiments, too,
at times conducted by placing the gun
cotton directly on the object, and at other
times confining it, furnish no uniformly
Moreover, if 9 cylinders of gun cotton
produce no more effect on the object than
one cylinder (see Experiments A. 5a, 5^
and 6), it does not follow that in the first
case more total energy, corresponding to
the weight, was not developed. At all
events, even considering exclusively the
effect, wet gun cotton will have prefer-
ence over dry, in case it is desired to de-
stroy, by means of externally applied un-
confined charges, such objects as walls,
arches, iron plates, etc., where the sur-
face of contact between the gun cotton
and the object to be destroyed is the
Exfjeriment No. 13. â€” A shell, filled
with grains entirely coated with paraffin.
A priming cartridge, 31 mm. in diameter,
i65 grm. in weight, placed in a space left
vacant for it in the filling, failed to deton-
ate the filling of the shell. There was a
partial combustion of the charge.
Experiment No, 14. â€” A shell, filled
*with grains entirely coated with p-iraffin,
and containing a priming cartridge 31
mm. in diameter, bat weighing 100 grm.,
In case grains composing the filling of
the shell are not bound together by
means of melted paraffin, a very much
heavier, and therefore larger, priming
cartridge is necessary for detonation than
if this is the case.
Ej:periment No, 15. â€” A 21 cm. csist-
iron shell was filled with 4,200 grm. dry
granulated gun cotton, and placed on a
support formed of a double row of rails.
Five iron rails were placed side by side
on two wooden skids, four rails were
placed between the first named rails.
The skids were 1 meter apart, the rails
therefore had a bearing of 1 m.
The shell was covered with earth to a
depth of \ m. The action was very con-
siderable ; all the rails were broken, most
of them at several points, and in addition
a depression was formed in the ground ^
m. deep. A bomb-proof coveiing can,
therefore, no longer be made in th^ way.
2>. Action of Gun Cotton and Oun
Cotton Shells in Earth.
Experiment No. 16. â€” A 15 cm. shell,
filled as above with granulated gun cot-
ton, buried 1 m. deep in the earth, pro-
duces in light soil as well as in somewhat
heavy soil (sandy clay) a cone :
60 cm. deep and 2 mu in diameter.
Experiment No. 17. â€” A 15 cm. shell,
filled with 2,100 grm. ordinary gun-
powder, produces a cone :
50 cm. deep, 2 m.. long, and 1^ m. broad.
Experiment No. 18. â€” A 15 cm. steel
shell, 6 calibers long, filled with 8.9 kg.
granulated gun cotton, wet, containing
25 per cent, water, 1 kg. dry grains, and
a primmg cartridge weighing 35 grm., so
buried that the head was 1 m. under the
surface, the base ^ m., made a funnel :
1.3 m. deep and 4 m. in diameter.
E. Comparative Experiments with
Granulated Gun Cotton and Gur^
The earth in which the explosions took
place was light, clayey, sandy soil.
Experiment No. 19. â€” A tin canister,
3 calibers long, 7^ liters in capacity,
6300 grm. wet granulated gun cotton,) 8 mm.
300 " dry ** ** ** j cube.
5630 " = total dry weight,
was buried so that one end was 1.2 m.
COMPRESSED GUN COTTON FOR MILITARY USE.
under the Burface, the other 0.9 m. ; it
formed a cone in the explosion,
1.10 m. deep, and 3.30 m. in diameter.
Experiment No. 20. â€” An explosive
charge of the same form as in Experi-
ment 19, but composed of disks of wet
gun cotton, 8.3 kg. in dry weight, and
furnished with a 60 grm. priming car-
tridge, was buried as in Experiment 19 ;
it formed a cone in the explosion,
1.30 m. deep and 4.10 m. in diameter.
disks, 16.6 kg. in dry weight, provided
with a priming cartridge weighing 50
grm., buried as in Experiment 21, formed
a cone, in the explosion,
1.56 m. deep and 5.1 m. in diameter.
A piece of wrought iron 3 cm. thick,
10 cm. square in surface area, which, in
the tirst two explosions lay close under
one comer of the charge, in the second
two explosions 15 cm. below the charge
and parallel to its side wall, separated
C0NE8 OF EXPLOSION.
15 cmi shell filled with ordinary gunpowd'eV*.
A 15 cm. steel shell, 6 calibres long.witn 8 kg. granulated guncottom.
Experiment No. 21. â€” A tin canister,
6 calibers long, 15 liters in capacity,
filled with 11,150 grm. dry granulated
gun cotton (8 mm. cube in volume,
cubic weight 0.75) and a priming car-
tridge weighing 50 grm., was buried so
that one end lay 1.2 m. deep, the other
0.6 m., and formed, in the explosion, a
1.58 m. deep and 4.45 m. in diameter.
Experiment No. 22.â€” An explosive
charge, composed of wet gun cotton
from it by earth, was, in Experiments
Nos. 19, 21 and 22, compressed to an
equal degree, but in No. 20, somewhat
more than in the others. In Experi-
ments 19 and 20, the iron lay, as re-
marked, immediately against the charge,
and, under these circumstances, the
disks were more energetic in their ac-
tion than the grains.
Experiment No. 23. â€” A piece of iron
rail, 0.5 m. long, 10 cm. broad in the
base, 12 cm. high, was placed in a ditch
VAN nostband's enqineebino magazine.
1.25 m. deep, resting on two pieces of fir,
10 square centimeters in cross-sections,
so as to leave 25 cm. between bearings.
Earth was thrown over the rail to a
depth of 25 cm. above the head. A tin
canister, like the one employed in Ex-
periment No. 19, filled with 5,620 grm.
dry grains and a 10 grm. .priming car-
tridge, was placed on the earth with its
axis perpendicular to that of the rail, and
the ditcQ filled up to the surface. The
canister was exploded â€” it cut the rail
squarely across, dividing it into three
parts, and besides, the base of the rail
was driven 1 cm. deep into the wood.
The pieces of wood were otherwise un-
injured. The cone of explosion was :
1.10 m. deep, 3.10 m. in diameter.
The pieces of rail and the strips of
-wood were found at a depth of 1.50 m.
under the surface.
JExperiment No, 24. â€” A charge of wet
gun cotton disks, of the same dimen-
sions as the above-described tin canister,
8.3 kg. in dry weight, and provided
with a 50 grm. priming cartridge, was
applied as in Experiment No. 23 and
The iron rail was broken in al-
most the same manner as in No. 28,
except that there were only two pieces,
in each of which a piece was broken
oflf from the head of the rail near the
middle. The base of the rail did not
penetrate into the wooden supports, but
the latter were cut squarely and smoothly
in two. They evidently offered less re-
sistance than in Experiment No. 23.
With the exception of this break the
strips of wood sustained no injury.
The cone of explosion was :
1.5 m. deep and 3.5 m. in diameter,
hence, somewhat larger than in Experi-
ment No. 23. The pieces of rail and the
strips of wood were found buried at a
depth of 1.65 m.
The charges Nos. 23 and 24 broke up
the iron rails at a depth of 45 cm.
below them,, and threw out cones of ex-
plosion to a depth of 40 and 80 cm. re-
spectively. The pieces of rail and the
wooden supports were found pressed 90
cm. into the ground, and the sandy earth
was ground to dust to the same depth.
This experiment shows that gun cot-
ton in both forms acts not only when in
direct contact, but with great force even
at considerable distance.
From the comparative experiments it
appears that in sum total the action of
equal volumes of granulated gun cotton
and gun cotton disks is the same ; the
excess in weight of over a third has
no effect, especially when considerable
weights are used, and the object to be
destroyed is not in direct contact with
Whether, with other objects and under
other circumstances, the excess of weight
of the charge when disks are used over
that of grains, will be made effective re-
mains undetermined, but we believe from
all the preceding experiments that we are
forced to the conclusion that this can
only take place to a slight extent.
We are furthermore of opinion that it
is very doubtful whether, by the use of
heavier and more sudden explosives, as,
for instance, explosive gelatine, mixtures
of the nitrates of benzole and aniline
with nitric or hyponitric acid, in shells,
a greater effect will be obtained.
In actual firing, the shells will rarely
be in direct contact with the object which
they are to destroy, but will more gener-
ally be some distance from it ; e. g., in
case of arches and armor plates they will
not lie in contact therewith along their
entire length, but will either not be in
direct contact at all or but very slightly,
and at the smaller distances is just where
the degree of suddenness of action of an
explosive is most apparent.
In case of shells with thick cast-iron
walls, the increased suddenness of action
will probably have no other effect than to
pulverize the walls to dust â€” an effect in
many cases not at all desired.
It will be necessary, however, to test
the various explosives under circum-
stances which resemble actual practice, in
order to obtain comparative results of
their power and action.
We will quote here a few examples
from the above mentioned work of Lieu-
tenant General Brialmont :
Ordinary 21 cm. steel shells, containing
a charge of 14^ kg. of gunpowder, firea
at an elevation of 45"^ from the Erupp 21
cm. forged mortar, penetrated from 2 to
2.60 m. into the sandy earth of the firing
ground at Meppen, and threw out ellipti-
cal cones of explosion â€”
GOMPBF66BD GUN COTTON FOR MILITAKY USE.
1.20 to 1.40 m. deep.
3.20 to 4.80 m. long.
3.20 to 4 00 m. broad.
Fired at 28** and 60^^ elevation, the action
was less. A steel torpedo shell, 6 calibers
long, containing a charge of 36 kg. of
gunpowder, fired at 35Â° elevation, pro-
duced a cone of explosion,
2.40 m deep and 4.80 m. in diameteri
corresponding to a mean displacement of
16 cabic meters of earth.
Arches, constructed of the best b6ton,
1.45 m. thick, require the following thick-
nesses of sandy earth to protect them
against various projectiles fired from the
21 cm. mortar :
CONE8 OF EXPLOSION.
16 kg. guncotton in ditkt, equal quantity granulated guncotton.
IS . 83 and 84t.
CONES OF EXPLOSION.
8 kg. guncotton in ditkt, equal quantity granulated guncotton.
1.00 to 2.20 m. deep,
3.20 to 5.00 m. long,
2.60 to 5.00 m. broad,
<K)rresponding to a mean displacement of
â€¢earth of 7 cubic meters.
The 21 cm. steel ^n cotton shells pene-
rate 4 m. deep, lying nearly horizontal,
and throw out cones of explosion.
Ordinary shells, : 2.50 m.
Steel shells, charge 14t^ kg. gun-
powder : 8 to 8.60 m.
Torpedo shell filled with gun cot-
ton :5 m.
But this thickness of earth covering of
5 m. cannot be attained in practice, as the
fortification works will have to be too
high and too costly. It is, therefore, pro-
VAN NOSTBAND's ENGINEERING MAGAZINE.
posed to omit the earth covering entirely,
and to replace it by a layer of granite or
porphyry 0.80 m. in thickness, or by a
bed of Portland cement 1 m. to 1.20 m.
The experiments in Silberberg in 1869
showed, however, that even this covering
will not suffice against the projectiles of
the forged mortar charged simply with
gunpowder, as these projectiles produc-
ed depressions of j to f m., so that a
second shell striking the same point
would penetrate the arch.
Lieutenant General Brialmont thinks,
therefore, that it is not possible to pro-
pose anything definite on this subject as
yet, but considers it preferable to con-
struct the arches of the best be ton, made
1 to 1.50 m. thick, and covered with at
least 3 m. of earth. In case this is not
sufficient, a part of the earth must be re-
placed by beton, or the earth covering
must be increased, or an arch of sheet-
iron may be inserted under the beton
arch, which last is the simplest and cheap-
This, it is evident, approaches the ar-
We believe, however, that even this
may be greatly damaged by means of
large charges of gun cotton.
From all this it is evident that Lieu-
tenant General Brialmont considers the
power of the gun cotton shell, and its
effect on the future construction of earth-
works, as very great.
SuBMAioNB Explosions with Compressed
Explosion of the Iron Tug -boat Mathias
fStinnes /., Sunk in the JRhine near the
Bailroad Bridge of jRheinhauaen^ be-
Conducted by the author and engineer
The tug- boat was a strong iron vessel,
dating from the earhest times in which
such vessels were built, constructed es-
pecially solidly in all its parts.
She lay with the stern 200 m. from the
railroad bridge, which stood on massive
piers, and 100 m. out from the right bank
of the Rhine, extending thence with its
entire length down stream almost in the
direction of the current. The stern at
mean low water was about 2 m., the bow
about 6 m. under water.
The vessel was to be cleared away to a
certain depth of water, so that evidently
the stem and center had to be removed.
The current is so strong that a diver can-
not descend without assistance.
A wooden Rhenish flat boat was there-
fore so arranged that an iron cylinder was
laid square across its deck, containing on
the end extending over the flat boat an
iron ladder, which could be turned in its
support. When the ladder hung free
vertically it was held by a hand screw,
but it could also be rested on the sunken
vessel, on parts which had fallen oflF, or
on the flatter parts of the river bottom,
and rose in all cases 2 m. above the
shaft. On the ladder a shild f m. broad
was fastened, which diverted the current
from it. The ladder and shield could be
raised and lowered by means of a hand-
screw. By means of the ladder the diver
could reach the vessel, and, protected by
the shield, could work readily, mostly with
the left arm.
A second flat boat of the largest kind
was provided with a solid deck and &
crane, by means of which and an iron
chain the parts separated by the explo-
sions were raised.
Although large chai*ges could not be
used on account of the proximity of the
railroad bridge, on which account heavy
shocks had to be avoided, they would
have been of no avail, but would more
likely have been detrimental.
No charge, however large, even if 1,000^
kg. of the most powerful explosive had
been detonated at once, would have de-
stroyed the vessel in such a way that the
separated parts could be raised and re-
moved. It would have left a conglom-
eration of parts of the vessel which, ad-
hering firmly, would not have permitted
the removal of the separate parts or the
work of the divers.
The question was how to remove separ-
ate parts by charges not too great, and
then to raise these parts by means of the
crane on the flat boat. Wooden chests
were therefore charged with 10 kg. com-
pressed gun cotton, and used either sep-
arately or occasionally two at the same
The diver descended to the vessel,
placed the charge in position, which often
required hours on account of the strongs
current, ascended ; the ladder was raided,
the flat-boat went out to the middle of the
COMPRESSED GUN COTTON FOR MILITARY USE.
stream, and the explosion was effected
The boat returned, the diver descend-
ed, fastened a chain to the loose parts of
the vessel, an operation which again re-
quired several hours, on account of the
exceedingly great difficulties, and an at-
tempt was then made to raise the parts,
which generally succeeded. Often the
attempt failed, however, as the parts
were still fast bound to the vessel, and
the strong crane could not tear them
The iron planks, the ribs, the wheel,
gradually the boiler, parts of the wheels,
parts of the shaft and the machinery
appeared in turn. The shaft was a cy-
linder of the best steel, 15 cm. thick,
and was acted on by a double charge,
hence by 20 kg. gun cotton, cutting it
across in several places.
Great as was the action of the gun
cotton, over 100 explosions, in which
1,200 kg. gun cotton were used, were
found necessary to clear the water to the
required depth. The greater part of the
stem of the vessel was removed, the rest
was forced into the sand of the stream by
the foirce of the explosions ; the bow of the
vessel till beyond the wheel shaft was
little disturbed; it lay, however, below
the required depth of water.
It is shown again, in this example,
that the annihilation of the vessel by
means of charges of explosives is entirely
out of the question ; iron constructions
are particularly difficult to remove, unless
they are raised after the explosion or the
force of the explosion pushes them into
To sink a floating vessel is quite another
Charges of 20 kg. of gun cotton, ap-
plied externally to a suitable part of the
vessel, and lying in direct contact, will
burst through the sides of the vessel, but
whether they will so disturb it as to make
it sink is a question. 2So far as relates to
its action at a distance, we have observed
that in explosions in deep water, at a
distance of 100 m. from a charge as much
as 100 kg. in weight, only a light shock
is given to floating material, such as ves-
sels, and that, on the contrary, the shock
produced by such an explosion is trans-
mitted through the solid earth to consid-
erable distances, 500 to 800 m., to other
solid substances standing on the ground,
such as buildings, for instance.
Wooden vessels are easily destroyed by
explosion, because after the explosion
they are removed by the water, by ebb
and flood tide, or by other currents.
We have destroyed a large number of
such sunken vessels on the coasts of the
North Sea, and at the mouths of the Jade
Charges of 100 kg. of gun cotton each,
placed in long chests, were lowered to the
wreck, or, when possible, fastened by
divers to the side-walls of the wrecks, and
In the case of small vessels, two or
three well-applied charges are sufficient ;
in the case of larger vessels, considerably
more are required.
Explosions at the Adlbrgbund.
In the Baltic Sea, between Bomholm
and Riigen, lies the Adlergrund, a shoal
formed by large rocks lying on the bot-
tom of the sea. At the shallowest places
the royal government, with a view to in-
creasing the depth of water, had some of
the rocks removed by vessels furnished
Divers went down, fastened chains
about the rocks, or attached clamps to
them ; the rocks were then raised. In
order to break up the rocks and to render
more easy the attachment of the lifting
machinery, many charges of 10 kg. gun
cotton each were placed on the bottom of
the sea, to a depth of 4 to 6 m., and de-
tonated. These explosions usually loosen-
ed from two to four blocks, each about 2
cubic meters in volume, and forced them
completely out of their original position,
so that they could be easily raised.
RockMasting in the Rhine^ vsith a View
to Deepening the Channel bttioeen Bin-
gen and Coblenz,
In many places rocks at the bottom of
the Rhine form shoals which impede nav-
igation, the best known and most dan-
gerous of which is the " Bingerloch."
From rafts and vessels a series of holes
is bored in the rocky bottom, 1 to 2 m.
deep, according to the amount of rock
material to be removed ; these are filled
with gunpowder, tamped with sand, and
the charge tired. After 10 or 20, or even
more blasts, vessels provided with div-
VAN NOSTBAND'S ENGINEERING MAGAZINE.
ing-bells are run over the Bpot, the
diving bell is lowered, and, by means of
picks and bars, the rocks are broken
loose, and are then raised through the
diving bell to the surface and loaded into
vessels held ready for the purpose.
We are of the opinion that if, in place
of the gunpowder, su'lden explosives are
used, the work of removing the debris,
which now involves the principal cost,
Ynll be greatly simplified and rendered
cheaper. It is also necessary with gun-
powder to deepen the bore- holes consid
erably below the point to which it is de-
sired to remove the rock ; fired with sud-
den explosives, the* rock will be removed
to the bottom of the boring, whereas by
the use of gunpowder the lower third of
the bore-hole remains intact. The sud-
den explosives are not used, because peo-
ple still fear those who decry them, say-
ing that a part of the explosive may re
main unexploded, and when the diving-
bell is lowered and the workmen proceed
to loosen the rocks, may give rise to after-
explosions, produced by the shocks in
striking it, which may cause serious acci-
This may be true of nitro-glycerine
preparations, which are not rendered in-
explosive by penetrating water, but in the
case of gun cotton the cartridges, as the
author has stated in his previous article,
may be easily so arranged that, after a
certain time, say 24 hours, they will be-
come thoroughly wet and rendered inex-
plosive and perfectly safe, as well from
the explosive priming cartridge, which
may still remain, as from the shocks of
Although advantages are gained by the
use of compressed gun cotton in such
work, we are nevertheless of the opinion
that neither gun cotton nor any other
sudden explosive can act so as to dispense
with the boring of the bore holes.
Externally applied charges do not, even
in case of considerable depth of water,
which acts as a kind of tamping, act so
strongly, but that the cost of explosives
will be too great.
We can conceive of an advantageous
method of carrying on the work with ex-
ternally-applied charges, without the use
of bore-h >les, only in case large surfaces
of rocks are to be removed to but slig'ht
depths, perhaps to 10 or 15 cm., in which
case bore-holes would even act disadvan-
tageously. The entire work of preparing
the borings and the removal of the rocks
is saved, and thus, in spite of the larg^e
amount of explosives employed, a rela-
tively cheaper and more rapid work is
EXAMINATION OP A DEPOSIT PROM THE CHANNEL WAY
OP THE U. S. S. RICHMOND.
Bt CHARLES B. MUNBOB.
Written for Yak Nostbamd^s Maoazikx.
The specimen examined was received
from P. A. Eng. A. B. Canaga, U.S.N.,
with the following statement :
" The two Martin's vertical water tubu-
lar boilers of the Richmond are con-
structed of wrought iron with composi-
tion tubes. The entire area of the tubes
in contact with the water is 5,208 square
feet. The copper steam pipe leading
to the two engines is 40 feet long and
1 foot in diameter. The copper ex-
haust pipes leading from the engines to
the condenser are each 10 feet long and
16 inches in diameter. The surfaces in
the cylinder and valve chest subject to
friction of metal on metal are all cast
iron ; and the area of this rubbing sur-
face for piston and slide valves is 116
square feet. The steam after being ex-
hausted from the engines is condensed in
a >eweirs surface condenser, the con-
denser tubes being of composition and
tinned. The area of the condensing sur-
face is 3,970 square feet. The condensed
steam falls to the bottom of the condenser
and is removed through the ^channel
way ' by the air pump. The sediment of
which you have a sample was taken from
this * channel way,' and about 12 bushels
of this muck-like sediment were removed
at the t^e your sample was taken. This
quantity had accumulated while the ship
steamed about 11,000 miles. The prin-
cipal lubricants used were olive and
sperm oils, but some tallow was also
used. The deposit, when removed, was