914 • D I V 
the water at any convenient place, and advance till it 
reaches to his eyes, while the end of the pipe is held by 
a perfon on the bank. If the diver can then breathe 
with eafe, and if no water forces itfelf into the pipe, 
which muft be left to float on the water, he may proceed 
till it covers his head, having fir ft taken the precaution 
to tie a ftrong rope to one of his arms. After this he 
may (top for fome time, and then gradually go deeper and 
deeper, making (ignals that he finds hirnfelf at eafe, by 
pulling the rope, or by fpeaking through the pipe. If 
a man exercifes hirnfelf in this manner for feveral days 
fucceffively, ftill increafing his depth, he will foon be able 
to dive boldly, and to move under the water with eafe 
and freedom : when he wifhes to afcend, he needs only 
unhook the weight, which will drop to the bottom ; and 
being then lighter than an equal volume of water, he 
will rife to the furface. To preferve the weight from 
being loft, a particular rope muft be employed, which 
may be let down to the diver upon his making a certain 
fignal, and which he may fuften to the weight before he 
unhooks it. By thefe diredlions, Frederic William Joa¬ 
chim, a huntfman by profeftion, dived in the above ap¬ 
paratus into the Oder, near Breflau, where the water was 
of confiderable depth and the current ftrong, on the 2+th 
of June 1797, before a great number of fpe&ators, and 
fawed through the trunk of a tree which was lying at the 
bottom. He fhewed alfo that he could have faftened 
funk bodies to a rope in order to be drawn up, and that 
in cafe any impediments fliould prevent the ufe ot the 
faw, fuch trunks might be hewn to pieces by an axe. It 
clearly appears, therefore, that two men furnifhed with 
fuch apparatus could faw to pieces large beams of wood 
lying at the bottom of rivers, or perform any other work 
in this apparatus, at a moderate depth under water. 
But it has been remarked, that a man at the depth of 
five feet tinder the water, cannot breathe without a co¬ 
pious machine ; and though fuch an one as that above 
defcribed will defend his bread and body from the pref- 
fure of .the water, yet though it be furnifhed with a pipe 
to breathe through, it will appear, from what follows, 
that in very deep water this will be impoflible. The 
air which furrounds the diver in the above machine 
amounts to fomewhat more than a cubic foot. Now if 
he inhales air through the pipe fcrewed to the machine, 
his body muft diftend a fpace equal to the volume of air 
inhaled, confequently he comprelfes fo much the air that 
furrounds him in the machine.. But as this is impoflible, 
on account of its too great refiftance, he does not obtain 
air fufficient to fupport life, and is almoft in the fame 
{late as if furrounded by water. To be convinced of 
the truth of this, let any one take a calk, equal in con¬ 
tent to one or two cubic feet; prefs his mouth againft 
the aperture of it, and try whether he can without dif¬ 
ficulty breathe back into it the air he has inhaled. A 
larger fpace around the diver in the machine would make 
breathing eafier, but would no.t render him fufficiently 
eafy to labour. The interior air in the machine, there¬ 
fore, muft be connected with the pipe oeftined for breath¬ 
ing, in order that it may be at freedom to dilate as his 
body is extended ; and it is only by a conftruclion of this 
kind, that a man can breathe while inclofed in fo fmall a 
fpace. The diver, therefore, muft fuffer the air inhaled 
through the mouth-piece to efcape through Iris noftrils 
into the machine ; and then the air in it will remain 
equally elaftic. The next time he draws breath, the .air 
in the machine will be forced out from it by the diftention 
of his body. By thefe means he will be able to breathe 
freely and eafily, at a moderate depth, for a long time; 
and thus the chief difficulty is overcome. 
But for the purpofe of defeending to very confiderable 
depths in the fea, a machine has been conftrudled by C. 
H. Klingert, as an appendage to the diver, filled with 
vital air. Fig. 5, in the preceding engraving, reprefents 
the machine, which coniifts of a hollow cylinder, termi¬ 
nating in two hollow truncated cones, in the fame manner 
I N G. 
as calks, and made exceedingly ftrong. By means of the 
interior confirmation of this machine a man can defeend 
to a great depth in the water, and live and move freely 
without a pipe to fupply him with atmofpheric air, be- 
caufe, being placed on a ftage k, without the machine, 
and furniihed with a harnefs and pipe like that before 
defcribed, he can obtain air from the fpace within if, 
which contains fifty-eight cubic feet. He may, therefore, 
remain under water two hours ; defeend from the ftage at 
pleafure, move about with freedom, and, by means of 
the machinery within, rife and defeend when he thinks 
proper, as will appear from what follows : 
Thofe who have made experiments with air will not 
doubt that fifty cubic feet of it are fufficient to maintain 
the life of a man for two hours ; and the poftibility of af- 
cendinganddefcendingatpleafuremay be thus explained : 
As this machine contains fuch a volume of air that it is 
lighter than water, it will require a confiderable weight 
to make it fink below the furface. That as little, how¬ 
ever, as poftible of the fpace deftined for containing air 
may be loft, lead may be employed, in the infide of the 
machine at b, fufficient to make it fink fo far that a cubic 
foot of it only fhall remain above the furface of the wa¬ 
ter. An additional weight then of one hundred pounds 
will not only deprefs it below the furface of the water, 
but make it fink to the bottom. But the fame thing may 
be effected without weights, by leffening the volume of 
the contained air. This is done by means of the piftonc, 
which fits clofely into the cylinder d, and which, by 
means of the rack c, the pinion f, the wheel g, and the 
endlefs ferew h, together with the winch i, can be moved 
either upwards or downwards. The machine, however, 
muft not only be ftrong and durable, but be conftrudted 
according to the depth to which it is deftined to defeend, 
and the prefTureon the pifton, that a man at fuch a depth 
may have fufficient ftrength to deprefs it by means of the 
winch, and thereby to enlarge again the volume of air. 
It will readily appear that, by railing the pifton, the ma¬ 
chine muft fink to the bottom ; and that, by deprefting it, 
the machine muft again afcend. If a machine be conftrudt- 
ed on a large fcale, it will be found, by calculation, that, 
if we eftimate the fridtion of the pifton, when made water¬ 
tight, at two hundred pounds, and that of the wheel- 
work at three hundred, though it may, perhaps, not be fo 
much, the winch at the depth of one hundred and twenty 
feet will not require a force of forty pounds. If the di¬ 
ameter of the pifton, however, be lelfened, and the cy¬ 
linder, in order that it may have the fame cubic content, 
be lengthened, and if a larger wheel be added to gain 
more power, fomething will be loft in regard to time ; 
but it can be eafily calculated to what greater depth the 
machine may be 11 fed, and how much the ftrength of a 
man can accomplifh. The higher the machine is in pro¬ 
portion to its diameter, the more fecurely will it remain 
perpendicular in the water, and the lefs danger will there 
be of its being overturned ; becaufe the diver is then 
nearer the center of gravity. That the fame advantage, 
how’ever, may be obtained with lefs expence, the wheel- 
work, together with the cylinder and pifton, may be 
omitted, and the machine conftrudled as far as the upper 
cover 0 ; but it muft be fo furnifhed with hooks for ballad, 
that the diver, when he has previoufly fcrewed on the 
pipe faftened to the machine, and placed hirnfelf on the 
ftage, may hang on ballaft, ftones, or other heavy fub- 
ftances, till it fink, and, by throwing them away, may 
again afcend at pleafure. The machine in this form is 
fimpler ; and, perhaps, to be preferred to the conftruc¬ 
tion with the pifton, wheel, and rack. 
The ends of the pipe Im, which proceed into the ma¬ 
chine, are fo applied that all the particles of air may gra¬ 
dually proceed through the lungs. Should it, however, 
after being ufed two hours, be no longer capable of fiip- 
porting life, the diver muft afcend with his machine, and 
be conveyed to the fhip or boat attending him, by means 
of the rope faftened to the ring n. He muft then l'crew 
