STEAM ENGINE. 
mentioned : and, indeed, it is certain that the account given 
in the Century of Inventions could not instruct a person who 
was not sufficiently acquainted with the properties of steam 
to be able to invent the machine himself. 
Desaguliers seems to have been too hasty in concluding 
that the captain had never made such an experiment as that 
of the wine-flask, because, in the single instances in which 
he tried it himself, he found the effect of the condensation took 
place in a much higher degree than reported by the captain. 
It is not difficult to conceive that a very small difference in 
the heat of the steam which filled the flask, and other circum¬ 
stances, might create the whole of the difference in the 
result. And, on the whole, there is no reason to hesitate 
in believing that the captain actually took his hint of the 
condensation of steam from such an accident, and being 
of a very mechanical genius, he would naturally turn his 
thoughts towards the consideration of such a power; and 
the most obvious application of it would be to a machine on 
a construction similar to that described by the marquis. Or, 
if he really had been acquainted with, and considered the 
marquis’s engine, he would easily see that the new principle 
of condensation might, with great advantage, be combined 
with the former, and thereby produce an effect more power¬ 
ful than either of them could do alone. The only thing in 
the doctor’s account which cannot now be disapproved is, 
that Captain Savery destroyed the Marquis of Worcester’s 
books. Even if this is true, it may be accounted for; 
the captain must, first or last, have become acquainted with 
what had been before made public by the Marquis of Wor¬ 
cester ; and after having in his books spoken of his invention, 
and his new power or cause of motion, and finding the 
marquis’s inventions to be but little known, he might be 
tempted, in order to secure the whole credit and expected 
advantage to himself, to buy up the marquis’s books and 
burn them. But the grounds for this assertion are very 
slight, and will never prevent the conclusion, that the 
great principle of obtaining force from the pressure of the 
atmosphere, by the condensation of the steam of boiling 
water, was a discovery for which we are indebted to Captain 
Savery, who had also the merit of first reducing it to prac¬ 
tice in a most complete manner, in combination with the 
prior discovery of the marquis. 
M. Amontons' Tire-Wheel. —The French writers who 
have treated of the steam-engine, seldom fail to mention Pa¬ 
pin and M. Amontons as the first inventors of the method of 
raising water by steam, and speak of Savery as a person who 
put their ideas in execution, and brought them to perfec¬ 
tion : we think it right on this account to state what was 
done by M. Amontons and Papin, although the attempts of 
the latter to employ the force of steam are not entitled to any 
notice, either from their originality, or from their real merit. 
It is probable, that the news of the patent granted to Savery 
in 1698, for raising water, and occasioning motion to mill- 
work by the impelling force of fire, excited the attention of 
the French academicians, before the means by which it was 
to be accomplished were made public, so as to be known 
abroad, and that they were thus induced to attempt the 
same thing; for in June 1699, which is the same month that 
Captain Savery shewed his machine at work before the Royal 
Society, M. Amontons delivered a memoir to the Royal 
Academy of Sciences at Paris, entitled “ A commodious 
Way of substituting the Action of Fire instead of Men and 
Horses to move Machines.” 
This may be regarded as the first attempt to produce a 
circular motion by the means of fire, otherwise than by the 
aeolipile, or the fly of a smoke-jack: but as the motion of 
M. Amontons’ wheel was to be produced by the alternate 
dilatation and contraction of air, and not of the steam of 
boiling water, it is nothing in common with Savery’s ma¬ 
chine, except that the first cause of motion is that of fire. 
M. Amontons’ fire-wheel, as he called it, consists of a 
number of close buckets, or chambers, placed in the circum¬ 
ference of a hollow wheel, and communicating with each 
other by valves opening in one direction ; and a sufficient 
quantity of water is put into these buckets to fill about 
555 
one half of the number: another circle of similar buckets* 
but of larger dimensions, are placed on the outside of the 
circle of the former buckets ; these large buckets contain air, 
and each one has a pipe conducted from it to one of the 
water-buckets which are nearer to the centre: a part of the 
circumference of the wheel, which is about the level of the 
centre, is exposed to the fire of a furnace, so that each air- 
bucket that passes will be heated ; and also the lower part of 
the wheel is immersed in a cistern of cold water, so as to cool 
the same bucket again. The action of the machine may 
easily be understood. The air contained in the large bucket 
which is opposite the fire becomes heated and expanded, and 
by the pipe of communication it enters into that water- 
bucket which is at the lower side of the wheel, and pressing 
upon the surface of the water therein, causes it to mount 
up through the other chambers, in the direction in which 
the valves open from one chamber to the next; the water, 
being thus accumulated in the chambers at one side of the 
wheel, will give it a preponderating power to turn round 
upon its axis. This motion brings another air-bucket oppo¬ 
site to the fire, and the air therein expands in its turn, and 
again elevates the water in the interior chambers as much as 
it had descended by the motion of the wheel; a continual 
succession is thus kept up, and the air-buckets which have 
passed the fire descend into the cold water, and the air is 
thereby cooled and reduced to its former bulk. By the 
communication with the water-buckets, the pressure of the 
expanded air is removed from within them, and puts them 
in a situation to repeat their action. 
This machine is ingenious, and if a better application of 
fire, by rarefying water into steam, had not been discovered, 
it is possible that the invention of M. Amontons might have 
been further prosecuted. From his computations it would 
appear, that the machine he proposed would act with a con¬ 
siderable power; but as he exhibited no working model, or 
actual trial, it was never proved that the machine, if put into 
practice, would be capable .of producing any thing near the 
effect promised by his calculations. Leupold, in his « Thea- 
trum Hydraulicarum,” 1724, proposed an improved form 
of this fire-wheel; and steam-engines have since been made 
with mercury, or fluid metal, contained within a hollow 
wheel, which is to be always kept on one side with the 
mercury by the force of the steam : they have not been 
found to equal other modes of applying the force of steam. 
Such of our readers as are curious to know more of the con¬ 
struction of M. Amontons’ machine, can consult the origi¬ 
nal memoir; and they wall also find a full account of it, 
with a figure, in Martin and Chambers’ Abridgment of the 
Philosophical History and memoirs of the Royal Academy 
of Sciences at Paris, vol. i. 
Papin's Pretensions to the Invention of the Steam 
Engine. —M. Papin, to whom the French attribute the in¬ 
vention of the steam engine, was a doctor of physic, and 
professor of mathematics at Marpurg, in Germany, and in 
1680 he was elected a fellow of the Royal Society of London. 
In the following year, and whilst in London, he invented 
and published a method of dissolving bones, and other ani¬ 
mal solids, in water, by confining them in close vessels, 
which he called digesters, and which he made sufficiently 
strong to retain the steam and prevent all evaporation, so as 
to acquire a great degree of heat. About the same time Dr. 
Hooke, the most inquisitive experimental philosopher of that 
inquisitive age, observed that water could not be made to ac¬ 
quire above a certain temperature in the open air, and that 
as soon as it begins to boil, its temperature remains fixed, 
and an increase of heat only produces a more violent ebul¬ 
lition, and a more rapid waste. Papin’s experiments with 
his digester rendered the elastic power of steam very familiar 
to him, and when he left England, and settled as professorof 
mathematics at Marpurg, he made many attempts to employ 
this force in mechanics, and even for raising water. 
By his own account, it appears that he had made some 
experiments with this view in 1698, by order of Charles, 
Landgrave of Hesse, but without effecting any thing. This 
is all the reason the French have to consider him as the first 
inventor 
