F. (François) Arago.

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the caldron where gas is engendered ; let there be
besides a free lateral communication between the inte-
rior of tiiis axis and the interior of the gun's barrel, so
that, after having filled the interior of the axis, the steam


enters the gun barrel, and issues by the lateral horizontal
opening. Except as to intensity, this steam in escaping
will act like the gases disengaged from the powder in the
barrel of the gun when closed at the end, and pierced
laterally ; only, we should not have but a mere shock
as occurred in the instance of the sudden and harsh
explosion from the gun ; on the contrary, the rotatory
motion will be uniform and continuous, like the cause
which engenders it.

Instead of only one gun, or rather instead of merely
one horizontal tube, let several be adapted to the ver-
tical rotatory tube, and we shall have, with the exception
of some slight differences, the ingenious apparatus of
Hero of Alexandria.

Here we should, doubtless, have a machine in which
the steam of water creates motion, and may produce
mechanical effects of some importance ; it would be
truly a steam-engine. But let us hasten to add that it
would have no real point of contact, either in its shape,
or the moving power's mode of action, with the machines
of that kind now in use. If ever the reaction of a cur-
rent of steam becomes practically useful, we must, with-
out hesitation, refer the idea back to Hero ; though at
present the rotatory eolipyle can only be quoted here as
carving on wood is cited in the history of printing.*

* These reflections are applicable also to the project that Branca,
an Italian architect, published at Rome, in 1629, in a work entitled
Le Macliine, and which consisted in generating a rotatory movement
by directing the steam issuing out of an eolipyle as breathings, or in
a current, or on the pallets of a wheel. If, contrary to all probability,
steam is some day usefully employed in the simple form of blowing,
Branca, or the author, now unknown, from whom he may have bor-
rowed the idea, will take the first rank in the history of this new
species of machines. Relative to the machines of the present day, the
claims of Branca would be quite null.



In our manufacturing machines, in our packet-boats,
in our railways, the motion results directly from the
elasticity of steam. It is therefore of importance to seek
where and how the idea of this power first arose.

Neither the Greeks nor the Romans were ignorant
that the steam of water can acquire a prodigious me-
chanical power. They already explained, by the aid of
the sudden evaporation of a certain quantity of this
fluid, the frightful earthquakes which in a few seconds
hurl the ocean beyond its natural limits ; which over-
turned from their very foundations the most solid monu-
ments of human labour ; which suddenly create danger-
ous rocks in the midst of deep seas ; and which heave
up high mountains in the very centre of continents.

Whatever may be said of it, this theory of earthquakes
does not show that its authors had devoted themselves to
appreciations, to experiments, to exact measurements.
No one now ignores that at the moment when the incan-
descent metal flows into the founder's moulds of earth
or plaster, a few drops of any fluid contained in them
would suffice to occasion dangerous exi)losions. Not-
withstanding the progress of science, modern founders
do not always avoid such accidents ; how then could the
ancients entirely keep clear of them ? Whilst they cast
thousands of statues, splendid ornaments of their temples,
of their public places, of their gardens, of the private
dwellings of Athens and of Rome, misi'ortunes must have
occurred; the artisans discovered the immediate cause.;
the philosophers, on the other hand, following out the
spirit of generalization, which was the characteristic of
their schools, saw in them miniatures, or true images, of
Etna's eruptions.


All this may be true, without having the least impor-
tance in the history that now occupies us. I have not
even insisted, I aeknowledge, so much on these slight
lineaments of ancient science relative to the power of
steam, but in order to live at peace, if possible, with the
Daciers of both sexes, with the Dutens of our own

Both natural and artificial powers, before becoming
really subservient to the use of man, have almost always
been adopted for objects of superstition. Nor will the
steam of water be an exception to the general rule.

The chronicles informed us that on the banks of the
Weser, the god of the ancient Teutones sometimes indi-
cated his displeasure to them by a sort of thunder-clap,
which was immediately followed by a cloud that filled
the sacred area. The image of their god Busterich,
found, it is said, in some excavations, clearly reveals the
way in which the pretended prodigy was obtained.

The statue was of metal. The hollow head contained
an amphora of water. Wooden plugs closed the mouth
and a hole above the forehead. Some charcoal, adroitly
placed in the cavity of the cranium, gradually warmed

* For the same reason, I cannot dispense with here relating an
anecdote, which, notwithstanding its romantic style, and containing
what we now know to be contrary to the way in which steam acts,
still shows the high opinion that the ancients had formed of this me-
chanical agent. It is related that Anthemins, Justinian's architect,
occupied a house next door to that of Zeno, and to annoy that ora-
tor, who was his declared enemy, he placed in the ground floor of his
own house several cauldrons containing water; that from an opening
made in the lid of each of these there proceeded a flexible tube, which
was conducted into the party-wall and up to the beams that supported
the floors in Zeno's house; in short, that those floors heaved as if
there had been a violent earthquake, as soon as fire was applied to
the boilers.


the fluid. Soon the steam that was generated made the
tompions fly out with a great report ; then it escaped
in two violent jets, and formed a thick cloud between the
god and his stupefied worshippers. It would appear
that in the middle ages some monks thought the inven-
tion a good prize, and that the head of Busterich has not
acted before assembled Teutones only.*

In order to meet with useful notions on the properties
of steam, after the first glimpses given by the Greek
philosophers, we are obliged to pass over an interval of
twenty centuries. It is true that then some precise, con-
clusive, and irresistible experiments follow upon conjec-
tures devoid of pi'oofs.

In 1605, Flurence Rivault, gentleman of the bed-cham-
ber to Henry IV., and preceptor to Louis XIII., discovers,
for example, that a shell or bomb, if made thick and con-
taining water, when placed on the fire after being well
closed, (so as to prevent the steam from expanding freely
in the air in proportion as it is generated, will sooner or
later explode. The power of steam is here found char-
acterized by a clear and, to a certain degree, sensitive
proof, with numerical appreciations ; but it is still pre-
sented to us as a terrible means of destruction.!

* Hero of Alexandria attributed the sounds, the objects of so much
controversy, issuing from the statue of Memnon wlien the rays of the
rising sun shone upon it, to the passage, through certain openings, of
a current of steam that the solar heat was deemed to have produced
at the expense of the fluid with which the Egyptian priests, it is said,
provided the interior of the pedestal of the Colossus. Solomon de
Cans, Kircher, &c., have gone so far as to wish to discover the spe-
cial arrangements by which the theocratic fraud took possession of
credulous imaginations; but all these suppositious lead us to think
that they have not guessed right, even if there be, in this respect, any
thing to guess.

t If any learned man were to think that by stopping at Flurence


Some eminent minds did not stop short at this meagre
reflection. They conceived that mechanical forces, as
well as human passions, must become useful or injurious,
according as they are well or ill directed. In the special
instance of steam, the simplest arrangement suffices to
adapt this redoubtable elastic power to productive labour ;
which, according to all appearances, shakes the earth from
its very foundations, which surrounds the furnace of the
statuary with real dangers, and which shatters the thick-
est bomb into a hundred fragments !

In what state does this projectile exist before its ex-
plosion ? The lower part contains some very hot water,
but still fluid ; the rest of the cavity is filled with steam.
This steam, it being the characteristic trait of all gaseous
substances, exerts its action equally in every direction :
it presses with similar intensity on the water and on the
metallic envelope that contains it. Let us apply a tap to
the lower part of the bomb. As soon as it is open, the
water, being urged by the steam, will rush out with ex-
treme swiftness. If the tap opens into a tube, which,
after curving round the exterior of the shell, rises up ver-
tically, the water, being forced to change its course, will
rise up in the tube in proportion to the elasticity of the
steam ; or, for it is the same thing though in other words,

Rivault I have not p;one back far enough; if he were to borrow a quo-
tation from Alberti, who wrote in 1411 ; if, according to tliat author,
he were to tell us that from the beginning of the fifteenth century, the
lime-burners feared much for themselves and their kilns, from the ex-
plosion of pieces of limestone fortuitously containing some cavities, I
should answer that Alberti himself was ignorant of the real cause of
those terrible explosions, for he attributed them to the air in the small
cavities being transformed into steam by the action of flame. I must
remark, in conclusion, that a piece of limestone, accidentally hollow,
would not have afforded the means of numerical appreciation of which
Rivanlt's experiment seems susceptible.


the water will rise in proportion to its temperature. The
only limits of the ascending movement will be the resist-
ance of the walls of the apparatus.

For our bomb let us substitute a thick metal caldron,
of vast capacity, and nothing will prevent our carrying
large quantities of fluid to indefinite heights by the sim-
ple action of steam ; we shall have constructed, in the full
meaning of the word, a steam-engine capable of emptying
or exhausting.

You now know the invention which France and Eng-
land have disputed upon, as formerly seven towns of
Greece claimed respectively the honour of having been
the cradle of Homer. On the other side of the Chan-
nel the honour is assigned to the Marquis of Worcester,
of the illustrious house of Somerset. On this side of the
Straits, we feel that it belongs to a humble engineer,*
almost entirely forgotten in biographical works ; to Solo-
mon de Cans, born at Dieppe, or in its environs. Let us
cast an impartial glance on the claims of these two com-

Worcester, deeply implicated in the political intrigues
of the latter years of the i-eigns of the Stuarts, was con-
fined in the tower of London.

" Que faire en p.areil gite, a moins que I'on ne songe? "
What could we do in such a bed but dream?

* The term "un humble ing^nieur" is hardly applicable, for De
Caus was, before the year 1612, engineer and architect to Louis XIII.,
King of France; he then entered the service of t!ie Elector Palatine,
who married the daughter of James I., with whom he came to Eng-
land, and was employed by the Prince of Wales in ornamenting Eich-
mond Gardens. His work was entitled Les Raisons des Forces Mou-
vcmtes, nvec cUverses; Mnchines tant utiles que plnisantes. In Partington's
Lectures on the Steam Engine, he quotes a book by Isaac De Caus,
"natif de Dieppe;" it is named Nouvelle Invention de lever V Eau plus
hant que sa source, avec quelques Machines movmintes par le nioyen de
fEau; it is a folio volume without date or place. — Translator.


Now one day, according; to tradition, the lid of the
saucepan, in which his dinner Avas being cooked, suddenly
rose. Worcester then considered the strangeness of the
phenomenon that he had just witnessed. The thought
now occnri-ed to him that the same power which had
raised the lid might become, under certain circumstances,
a useful and convenient motive power. After recovering
liis liberty, he described, in 1663, in a book entitled Cen-
tury of Inventions* the means by which he intended to
realize his idea. The essential part of these means, as
far at least as they can be understood, is the bomb half
filled with a fluid, and the vertically ascending tube, as
we just now described.

This bomb, this same tube, are drawn in the Reason
of Moving Forces, a work by Solomon de Caus. There,
the idea is presented clearly, simply, and without any
pretension. Its origin has nothing romantic in it ; it is
not connected with the events of civil war, nor with a
celebrated state prison, nor even with the rising of the
lid of a prisoner's saucepan ; but, what is of intinitely
more importance in a question of priority, it is, by its
publication, forty-eight years older than the Century of
Inventions, and foi'ty-one years anterior to Worcester's

Thus reduced to a comparison of dates, the debate
seemed to be brought to a close. Indeed, how maintain
that 1615 had not preceded 1663? But those persons
whose principal aim was to expel any French name from
this important chapter of the history of the sciences, im-
mediately changed their ground, as soon as they had

* It is expressly stated on the title-page of this pamphlet, that it
was written in the year 1655, though not published till imZ.— Trans-


occasioned the Reasons of Moving Forces to be disin-
terred from tlieir dusty shelves. Without hesitation tliey
pulled down their former idol ; the Marquis of Worcester
was sacrificed to the desire of annulling the claims of
Solomon de Cans ; the bomb placed on a burning brazier
with its ascending tube, ceased at last to be the true germ
of the present steam-engine ! *

As to myself, I do not grant that the man was of no
utility who, reflecting on the enormous elasticity of steam
when greatly heated, was the first to perceive that it
might be used to raise great quantities of water to all
imaginable heights. I cannot admit that no mention is
due of the engineer who was also the first to describe a
machine adapted to realizing such effects. Let us not
forget that we cannot judge soundly of the merit of an
invention, without transferring ourselves in imagination
to the epoch in which it was made ; without expelling
from our mind for the time all the knowledge that subse-
quent centuries have poured in upon us. Let us imagine
an ancient mechanic, Archimedes, for example, consulted
on the means of raising the water contained in a vast,
closed, metallic recipient, to a great height. He would
certainly speak of great levers, of single or multiplied
pulleys, of a windlass, perhaps of his ingenious screw ;
but what would be his surprise if to solve the problem
some one would be content with a fagot and a match ?

* In Les Raisons des Forces Mouvantes, it is evident that De Caus
ascribes tlie force wliicli shivered tlie shell entirely to the air; and he
seems to consider that tlie force of the air proceeded from the water
which exhaled in it. M. Arago cannot be borne out in saying, of those
who do not arrive at his conclusions, that "d'dcarier tout nom Fran-
gais" was their principal thought. We know not to whom he alludes
in assigning such a base motive, but the assertion infringes greatly on
the impartiality which he promised us. — Translator.


"Well, I must ask, should we dare to refuse the epithet of
invention to a proceeding at which the immortal author
of the earliest and true principles of statics and hydro-
statics would have been astonished ? The apparatus of
Solomon de Caus, that metallic envelop in which an
almost indefinite motive power is created by the aid of a
fagot and a match, will always figure nobly in the his-
tory of the steam-engine.*

It is very doubtful Avhethcr Solomon de Caus, or Wor-
cester ever had their apparatus made. This honour be-
longs to an Englishman,! to Captain Savery.J I compare

* It has been printed that G. B. Porta had given in his Spiritali, in
1606, nine or ten years before the publication of Solomon de Caus's
work, the description of a machine intended to raise water by means
of the elastic power of steam. I have elsewhere shown that the learned
Keapolitan does not spenl; either directly or indirectly, of a machine in
the passage alluded to ; that his aim, that his only aim, was to deter-
mine experimentally the relative volumes of water and of steam; that
in the small physical apparatus employed for this purpose, according
to the very words of the author, the steam could not raise the water
more than a few centimetres (some inches); that in the whole descrip-
tion of the experiment, there is not a single word implying the idea
that Porta knew the power of this agent, and the possibility of apply-
ing it to the production of a ujeful machine.

Is it thought that I ought to have quoted Porta, at least on account
of his researches on the transformation of water into steam? But I
should then say that the phenomenon had already been studied with
attention by Professor Besson of Orleans, about the middle of the six-
teenth century, and that one of the treatises of that mechanic in 1569,
contains a special essay on determining the relative volumes of water
and steam.

t Bonnain says that, after Kircher's death, a model was found in his
museum of a machine which tliat enthusiastic writer had described in
1656, and which differed from that of Solomon de Caus only in one re-
spect — the motive steam was engendered in a vessel totally distinct
from that containing the water to be elevated.

I Thomas Savery was a sailor, but, not being in the Royal Navy, is
styled Esquire Savery in the Royal Society correspondence. Nor is
our author quite right in supposing this was the first engine. Tlie


the machine constructed by that engineer in 1698, to that
of his predecessors, although he introduced some essential
modifications into it ; that, amongst others, of generating
the steam in a separate vessel. Although it may signify-
little relative to principle whether the steam be generated
from the same water that is to be elevated and in the
same caldron where it is to act, or from a separate vessel
to be admitted at will through a tube of communication
furnished with a tap above the fluid that is to be expelled,
it is not so in practice. Another alteration, still more
useful and worthy of special mention, equally due to Sa-
very, will be more appropriately treated of in the article
that we shall devote in the sequel to the labours of Papin
and Newcomen.

Savery had entitled his work The Miner's Friend.
But the miners did not show themselves sensible of
his politeness. With only one exception, none of them
ordered his machine. They have been used only to dis-
tribute water through various parts of palaces and coun-
try houses, parks and gardens ; recourse has been had to
them only to overcome a difference of levels of twelve or
fifteen metres. We must keep- in mind, however, that
the danger of explosion would have been very great, if
the immense power had been given to this apparatus
that the inventor asserted they could bear.

Marquis of Worcester did actually make au "apparatus" to drive
water up by fire ; aud Cosmo de Medici, Grand Duke of Tuscauy, de-
scribes in his Biai-y that he saw it in operation at Vauxhall, in the
year 1C56, — " went beyond the palace of the Archbishop of Cauter-
bury, to see au hydraulic machine invented by my Lord Somerset,
Marquis of Worcester. It raises water more than forty geometrical
feet by the power of one man only ; and in a very short space of time
will draw up four vessels of water through a tube or channel not more
than a span in width." Savery's engine was an improvement upon
this by the introduction of a vacuum. — Translator.


Notwithstanding the incompleteness of Savary's prac-
tical success, this engineer's name deserves to hold a very
distinguished place in the history of the steam-engine.
Those persons whose life has been devoted to speculative
exertions, are little aware of the distance there is between
the pi'oject, apparently the most studied, and its reali-
zation. Not that I presume to say, with a celebrated
German Professor, that Nature always exclaims no, no !
when we wish to raise a corner of the veil with which she
covers herself; but, in following up the same metaphor,
it may be permitted to assert that the enterprise increases
in difficulty, in delicacy, and in uncertainty, in proportion
as it requires the united efforts of moi'c artists, and the
employment of more matei-ial elements ; in these various
respects, and considering the nature of the epoch, no one
can have felt himself more unfavourably situated than


I have spoken hitherto of steam-engines, the resem-
blance of which to those that now bear that name may
be more or less contested. We shall now treat of the
modern steam-engine, of that which is in use in our man-
ufactories, in our boats, at the entrance of nearly all our
wells and mines. We shall see it created, then enlarge
and develop itself, sometimes by the inspiration of clever
men, sometimes by the prickings of necessity, for neces-
sity is the mother of genius.

The first name that we shall meet in this new period
is that of Denis Papin. It is to Papin that France will
owe the honourable rank that she may claim in the his-
tory of the steam-engine. Still the highly legitimate
pride, which these successes inspire us with, will not be
unmixed. We shall find the claims of our countrymen


nowhere but in foi'eign collections ; his principal works
will be published beyond the Rhine ; his liberty will be
menaced by the revocation of the edict of Nantes ; it Avill
be in a painful exile that he will temporarily enjoy that
privilege of which studious men are most jealous, tran-
quillity of mind. Let us hasten to throw a veil over the
deplorable results of our civil discords ; let us forget that
fanaticism was attached to the religious opinions of the
physicist of Blois and return to mechanics ; in this re-
spect at least the orthodoxy of Papin has never been

There are two things to be considered in every ma-
chine ; on one hand the moving power, on the other the
arrangement, inore or less complicated, of the fixed and
movable parts, and by the aid of which the moving
power transmits its action to the resistance. At the
height to which mechanical knowledge has now attained,
the success of a machine intended to produce great effects,
depends chiefly on the moving power, on the way of ap-
plying it, and economizing its action. And therefore it
was to produce an economical moving power capable of
making the piston of a large cylinder oscillate constantly,
that Papin devoted his life. Then to obtain from the
oscillations of the piston the power required to turn the
stones of a corn mill, the cylinders of a flatting mill, the
paddle-wheels of a steamboat, the bobbins of a spinning
mill : to raise the heavy hammer that strikes with re-
doubled blows enormous masses of incandescent iron, on
its coming out of the reverberating furnace : to cut thick
bars of metal with the two jaws of the shears, as we cut
ribbon with sharp scissors : those are, I repeat it, so many
problems of a very secondary order, and that would not
puzzle the commonest engineers. We may employ our-


selves, therefore, exclusively with the means by the aid
of which Papin proposed to induce his oscillating motion.

Let us imagine a large vertical cylinder, open at top,
and its base resting on a metallic table, pierced with a
hole that a cock can either close or open at will.

Introduce a piston into this cylinder, that is to say, a
circular plate, filling it entirely but movable, that shall
exactly close it. The atmosphere will rest with all its

Online LibraryF. (François) AragoBiographies of distinguished scientific men (Volume 2) → online text (page 29 of 38)