D I V 
off the pipe, open the top o, and, by means of a pair of 
bellows expel the air from the machine ; or immerfe it, 
when open, in the water ; on the pouring out of which, 
afterwards, the machine will be filled with frefh atmo¬ 
spheric air. Two fmall oars may be added to the ftep or 
feat, in order to make a few movements, and alfo an an¬ 
chor or grapnel to fallen the machine to the bottom, that 
the diver may be enabled to walk about with the pipe at 
freedom, for the purpofe of examining funk bodies, and 
difcovering the propereft method of railing them. For 
greater fecurity, in cafe any accident fiiould happen to 
the machine, an apparatus may be applied to the pipe, 
that the diver can leave the machine and rife without 
it; which he might eafily effedt, by throwing away the 
weights fufpended from his harnefs, and by retaining be¬ 
tween his body and harnefs a fufficiency of air for amend¬ 
ing. By thele means he might leave the machine, even 
if he were not acquainted with fwimming. At p, is a 
lantern, the ufe of which is to afford the diver light in 
the water; becaufe the folar light is often prevented 
from penetrating to very great depths by the many foreign 
particles mixed with that fluid, and is therefore incapa¬ 
ble of rendering bodies lying at the bottom of it vifible ; 
and becaufe other occafions may occur when artificial 
light will be necefiary. Borelli invented a machine of 
this nature, called a diving-bladder. It was conftructed of 
brafs or copper to protect the diver’s head, and was fixed 
to a jacket with air-pipes fimilar to the preceding. 
A diving apparatus has been invented by Mr. Bufh- 
nel, of Connedticut, called a fubmarine vejfel, the deftina- 
tion of which was to blow up and deftroy the Britifh 
{hips and veflels employed in the American war. This 
machine is defcribed in the Tranfadtions of the American 
Philofophical Society. The external fliape bore fome 
refemblance to two upper tortoife {hells of equal fize 
joined together. The inlide was capable of containing 
the operator, and air fufficient to fupport him thirty mi¬ 
nutes without receiving frefh air. At the bottom, op- 
pofite to the entrance, was fixed a quantity of lead for 
ballaft. At one edge, which was diretlly before the 
operator, who fat upright, was an oar for rowing forward 
or backward. At the other edge was a rudder for fleer¬ 
ing. An aperture, at the bottom, with its valve, was 
deligned to admit water, for the purpofe of defeending; 
and two brafs forcing-pumps ferved to eject the water 
within, when necefiary for afeending. At the top there 
waslikewife an oar for afeending or defeending, or con¬ 
tinuing at any particular depth. A water-gauge, or ba¬ 
rometer, determined the depth of defeent, a compafs di¬ 
rected the coitrfe, and a ventilator within fupplied the 
vefiel with frefh air. 
When the navigator would defeend, he placed his foot 
upon the top of a brafs valve, depreffing it, by which he 
opened a large aperture in the bottom of the vefiel, 
through which the water entered at his pleafure; when 
he had admitted a fufficient quantity, he defeended gra¬ 
dually ; if he admitted too much, he ejected as much as 
was necefiary to obtain an equilibrium, by the two brafs 
forcing-pumps, which were placed at each hand. When-' 
ever the vefiel leaked, or he would afeend to the furface, 
he alfo made ufe of thefe forcing-pumps. When he had 
obtained an equilibrium, he could row upward, or down¬ 
ward, or continue at any particular depth, with the oar, 
placed near the top of the vefiel, formed upon the prin¬ 
ciple of a (crew, the axis of the oar entering the vefiel; 
by turning the oar one way he raifed the vefiel, by turn¬ 
ing it the other way he depreffed it. The internal fliape 
of the vefiel verged towards an ellipfis, as near as the 
defign would allow; but every horizontal fedtion, al¬ 
though elliptical, was as near to a circle as could be ad¬ 
mitted. The body of the velfel was made exceedingly 
ftrong; and, to ftrengthen it as much as pofiible, a firm 
piece of wood was framed, parallel to the conjugate dia¬ 
meter, to prevent the (ides from yielding to the great 
prefiure of the incumbent water, in a deep immerlion. 
2 
I N G. ’ 915 
In the fore part of the brim of the crown of the ma¬ 
chine or vefiel, w-as a focket, and an iron tube pafling 
through the focket; the tube flood upright, and could 
Aide up and down in the focket fix inches: at the top 
of the tube was a wood-ferew, fixed by means of a rod, 
which parted through the tube, and ferewed the wood- 
ferew faft upon the top of the tube ; by pufiling the 
wood-ferew up againft the bottom of a fliip, and turning 
it at the fame time, it would enter the planks; when 
the wood-ferew was firmly fixed, it could be caft off by 
unferewing the rod, which faftened it upon the top of 
the tube. Behind the fubmarine vefiel was a place, 
above the rudder, for carrying a powder magazine, large 
enough to contain 150 pounds of powder, with the ap¬ 
paratus ufed in firing it, and was fecured in its place by 
a ferew. A ftrong piece of rope extended from the ma¬ 
gazine to the wood-ferew above-mentioned, and was faf¬ 
tened to both. When the wood-ferew was fixed, and to 
be caft off from its tube, the magazine was to be caft 
oft’likewife by unferewing it, leaving it hanging to the 
wood-ferew ; it was lighter than the water, that it might 
rife up againft the objedt, to which the wood-ferew and 
itfelf were faftened. Within the magazine was an appa¬ 
ratus, conftrudted to run any propofed length of time, 
under twelve hours; when it had run out its time, it 
unpinioned a ftrong lock refembling a gun-lock, which 
gave fire to the powder. This apparatus was fo pinion¬ 
ed, that it could not pofiibly move, till, by carting oft’ 
the magazine from the vefiel, it was fet in motion. 
The fkilful navigator or operator could fwim fo low on 
the furface of the water, as to approach very near a (hip, 
in the night, without fear of being difeovered, and might, 
if he chofe, approach the ftera or ftern above water, with 
very little danger. He could fink very quickly, keep at 
any depth, and row a great diftance in any direction he 
defired, without coming to the furface ; and, when he 
rofe to the furface, he could foon obtain a frefii fupply 
of air, when, if necefiary, he might defeend again, and 
purfue his cotirfe. The firft experiment made was with 
about two ounces of gunpowder, which were exploded 
four feet under water, to prove that powder would take 
fire under water. The fecond experiment was made with 
two pounds of powder, incloled in a wooden bottle, and 
fixed under a hoglhead, with a two-inch oak plank be¬ 
tween the hoglhead and the powder; the hoglhead was 
loaded with (tones as deep as it could fwim; a wooden 
pipe, defeending through the lower head of the hoglhead, 
and through the plank, into the powder contained in the 
bottle, was primed with powder. A match put to the 
priming, exploded the powder, which produced a won¬ 
derful effedt, rending the plank into pieces, demolifhing 
the hoglhead, and carting the ftones many feet into the 
air. After many other fimilar experiments, the operator 
was made to defeend, and continue at particular depths, 
without riling or finking, row by the compafs, approach 
a vefiel, go under her, and fix the wood-ferew, mentioned 
before, into her bottom, &c. until he was thought fuffi- 
cieotly expert to put any defign into execution. 
After thefe experiments, Mr. Bulhnel fent the naviga¬ 
tor of his fubmarine vefiel from New York, to deftroy an 
Englifh fifty-gun (hip, lying not far from Governor’s 
I (land. He went under the (hip, and attempted to fix 
the wood-ferew into her bottom, but ftr'uck, as he fup- 
pofes, a bar of iron, which paffes from the rudder hinge, 
and is (piked under the (hip’s quarter. Had he moved a 
few inches lie would probably have found wood where 
lie might have fixed the ferew; or, if the (hip were 
ftieathed with copper, he might eafily have pierced it: 
but not being well (killed in‘the management of the vef- 
fel, in attempting to move to another place he loft the 
(hip ; after feeking her in vain for fome time, he rowed 
fome diftance, and rofe to the furface of the water, but 
found day-light had advanced fo far, that he durft not 
renew the attempt. The adventurer faid that he could 
eafily have faftened the magazine under the ftern-of the 
fliip, 
