essay upon the subject of conveying swift intelligence, in which he
proposes to use large wooden letters in succession. The siege of Vienna
turned his attention to the business. His method is more cumbrous than
the French telegraph, but far less liable to error.
I tried it before I had seen Hooke's work, in the year 1767 in London,
and I could distinctly read letters illuminated with lamps in Hampstead
Churchyard, from the house of Mr. Elers in Great Russell Street,
Bloomsbury, to whom I refer for date and circumstance. To him and to Mr.
E. Delaval, F.R.S., to Mr. Perrot, of Hare Hatch, and to Mr Woulfe the
chemist, I refer for the precedency which I claim in this invention. In
that year I invented the idea of my present tellograph, proposing to
make use of windmill sails instead of the hands or pointers which I now
employ. Mr. Perrot was so good as to accompany me more than once to a
hill near his house to observe with a telescope the windmill at
Nettlebed, which places are, I think, sixteen miles asunder. My
intention at that time was to convey not only a swift but an
unsuspected mode of intelligence. By means of common windmills this
might have been effected, before an account of the French telegraph was
made public.
My machinery consists of four triangular pointers or hands [each upon a
separate pedestal, ranged along in a row], each of which points like the
hand of a clock to different situations in the circles which they
describe. It is easy to distinguish whether a hand moving vertically
points perpendicularly downwards or upwards, horizontally to the right
or left, or to any of the four intermediate positions.
The eye can readily perceive the eight different positions in which one
of the pointers is represented [on the plate attached to the article in
the "Transactions," but here omitted]. Of these eight positions seven
only are employed to denote figures, the upright position of the hand or
pointer being reserved to represent o, or zero. The figures thus denoted
refer to a vocabulary in which all the words are numbered. Of the four
pointers, that which appears to the left hand of the observer represents
thousands; the others hundreds, tens, and units, in succession, as in
common numeration.
[By these means, as Mr. Edgeworth showed, numbers from 1 up to 7,777,
omitting those having a digit above 7, could be displayed to the distant
observer, who on referring to his vocabulary discovered that they meant
such expressions as it might seem convenient to transmit by this
excellent invention.]
Although the electric telegraphs have long since superseded telegraphs
of this class in public use, the young people of Colonel Ingham's class
took great pleasure in the next summer in using Mr. Edgeworth's
telegraph to communicate with each other, by plans easily made in their
different country homes.
It may interest the casual reader to know that the first words in the
first message transmitted on the telegraph between Scotland and Ireland,
alluded to above, were represented by the numbers 2,645, 2,331, 573,
1,113 244, 2,411, 6,336, which being interpreted are,--
"Hark from basaltic rocks and giant walls,"
and so on with the other lines, seven in number. This is Mr. Edgeworth's
concise history of telegraphy before his time.
The art of conveying intelligence by sounds and signals is of the
highest antiquity. It was practised by Theseus in the Argonautic
expedition, by Agamemnon at the siege of Troy, and by Mardonius in the
time of Xerxes. It is mentioned frequently in Thucydides. It was used by
Tamerlane, who had probably never heard of the black sails of Theseus;
by the Moors in Spain; by the Welsh in Britain; by the Irish; and by the
Chinese on that famous wall by which they separated themselves from
Tartary.
* * * * *
All this detail about Mr. Edgeworth's telegraph resulted in much search
in the older encyclopædias. Quite full accounts were found, by the young
people, of his system, and of the French system afterwards employed, and
worked in France until the electric telegraph made all such inventions
unnecessary.
Before the next meeting, Bedford Long, who lived on Highland Street in
Roxbury, and Hugh, who lived on the side of Corey Hill, were able to
communicate with each other by semaphore; and at the next meeting they
arranged two farther stations, so that John, at Cambridge, and Jane
Fortescue, at Lexington, were in the series.
There being some half an hour left that afternoon, the children amused
themselves by looking up some other of Mr. Edgeworth's curious
experiments and vagaries.
MORE OF MR. EDGEWORTH'S FANCIES.
During my residence at Hare Hatch another wager was proposed by me among
our acquaintance, the purport of which was that I undertook to find a
man who should, with the assistance of machinery, walk faster than any
other person that could be produced. The machinery which I intended to
employ was a huge hollow wheel, made very light, withinside of which, in
a barrel of six feet diameter, a man should walk. Whilst he stepped
thirty inches, the circumference of the large wheel, or rather wheels,
would revolve five feet on the ground; and as the machinery was to roll
on planks and on a plane somewhat inclined, when once the _vis inertiæ_
of the machine should be overcome, it would carry on the man within it
as fast as he could possibly walk. I had provided means of regulating
the motion, so that the wheel should not run away with its master. I had
the wheel made; and when it was so nearly completed as to require but a
few hours' work to finish it, I went to London for Lord Effingham, to
whom I had promised that he should be present at the first experiment
made with it. But the bulk and extraordinary appearance of my machine
had attracted the notice of the country neighborhood; and, taking
advantage of my absence, some idle curious persons went to the carpenter
I employed, who lived on Hare Hatch Common. From him they obtained the
great wheel which had been left by me in his care. It was not finished.
I had not yet furnished it with the means of stopping or moderating its
motion. A young lad got into it; his companions launched it on a path
which led gently down hill towards a very steep chalk-pit. This pit was
at such a distance as to be out of their thoughts when they set the
wheel in motion. On it ran. The lad withinside plied his legs with all
his might. The spectators, who at first stood still to behold the
operation, were soon alarmed by the shouts of their companion, who
perceived his danger. The vehicle became quite ungovernable; the
velocity increased as it ran down hill. Fortunately the boy contrived to
jump from his rolling prison before it reached the chalk-pit; but the
wheel went on with such velocity as to outstrip its pursuers, and,
rolling over the edge of the precipice, it was dashed to pieces.
The next day, when I came to look for my machine, intending to try it on
some planks which had been laid for it, I found, to my no small
disappointment, that the object of all my labors and my hopes was lying
at the bottom of a chalk-pit, broken into a thousand pieces. I could not
at that time afford to construct another wheel of this sort, and I
cannot therefore determine what might have been the success of my
scheme.
As I am on the subject of carriages, I shall mention a sailing-carriage
that I tried on this common. The carriage was light, steady, and ran
with amazing velocity. One day, when I was preparing for a sail in it
with my friend and schoolfellow Mr. William Foster, my wheel-boat
escaped from its moorings just as we were going to step on board. With
the utmost difficulty I overtook it; and as I saw three or four
stage-coaches on the road, and feared that this sailing-chariot might
frighten their horses, I, at the hazard of my life, got into my carriage
while it was under full sail, and then, at a favorable part of the road,
I used the means I had of guiding it easily out of the way. But the
sense of the mischief which must have ensued if I had not succeeded in
getting into the machine at the proper place and stopping it at the
right moment was so strong as to deter me from trying any more
experiments on this carriage in such a dangerous place.
Such should never be attempted except on a large common, _at a distance
from a high_ road. It may not, however, be amiss to suggest that upon a
long extent of iron railway in an open country carriages properly
constructed might make profitable voyages, from time to time, with sails
instead of horses; for though a constant or regular intercourse could
not be thus carried on, yet goods of a certain sort, that are salable at
any time, might be stored till wind and weather were favorable.
When Bedford had read this passage, John Fordyce said he had travelled
hundreds of miles on the Western railways where Mr. Edgeworth's sails
could have been applied without a "stage-coach" to be afraid of them.
JACK THE DARTER.
In one of my journeys from Hare Hatch to Birmingham, I accidentally met
with a person whom I, as a mechanic, had a curiosity to see. This was a
sailor, who had amused London with a singular exhibition of dexterity.
He was called _Jack the Darter_. He threw his darts, which consisted of
thin rods of deal of about half an inch in diameter and of a yard long,
to an amazing height and distance; for instance, he threw them over what
was then called the New Church in the Strand. Of this feat I had heard,
but I entertained some doubts upon the subject. I had inquired from my
friends where this man could be found, but had not been able to discover
him. As I was driving towards Birmingham in an open carriage of a
singular construction, I overtook a man who walked remarkably fast, but
who stopped as I passed him, and eyed my equipage with uncommon
curiosity. There was something in his manner that made me speak to him;
and from the sort of questions he asked about my carriage, I found that
he was a clever fellow. I soon learned that he had walked over the
greatest part of England, and that he was perfectly acquainted with
London. It came into my head to inquire whether he had ever seen the
exhibition about which I was so desirous to be informed.
"Lord! sir," said he, "I am myself Jack the Darter." He had a roll of
brown paper in his hand, which he unfolded, and soon produced a bundle
of the light deal sticks which he had the power of darting to such a
distance. He readily consented to gratify my curiosity; and after he had
thrown some of them to a prodigious height, I asked him to throw some of
them horizontally. At the first trial he threw one of them eighty yards
with great ease. I observed that he coiled a small string round the
stick, by which he gave it a rotary motion that preserved it from
altering its course; and at the same time it allowed the arm which threw
it time to exercise its whole force.
If anything be simply thrown from the hand, it is clear that it can
acquire no greater velocity than that of the hand that throws it; but if
the body that is thrown passes through a greater space than the hand,
whilst the hand continues to communicate motion to the body to be
impelled, the body will acquire a velocity nearly double to that of the
hand which throws it. The ancients were aware of this; and they wrapped
a thong of leather round their javelins, by which they could throw them
with additional violence. This invention did not, I believe, belong to
the Greeks; nor do I remember its being mentioned by Homer or Xenophon.
It was in use among the Romans, but at what time it was introduced or
laid aside I know not. Whoever is acquainted with the science of
projectiles will perceive that this invention is well worthy of their
attention.
A ONE-WHEELED CHAISE.
After having satisfied my curiosity about Jack the Darter, I proceeded
to Birmingham. I mentioned that I travelled in a carriage of a singular
construction. It was a one-wheeled chaise, which I had had made for the
purpose of going conveniently in narrow roads. It was made fast by
shafts to the horse's sides, and was furnished with two weights or
counterpoises, that hung below the shafts. The seat was not more than
eight and twenty or thirty inches from the ground, in order to bring the
centre of gravity of the whole as low as possible. The footboard turned
upon hinges fastened to the shafts, so that when it met with any
obstacle it gave way, and my legs were warned to lift themselves up. In
going through water my legs were secured by leathers, which folded up
like the sides of bellows; by this means I was pretty safe from wet. On
my road to Birmingham I passed through Long Compton, in Warwickshire, on
a Sunday. The people were returning from church, and numbers stopped to
gaze at me. There is, or was, a shallow ford near the town, over which
there was a very narrow bridge for horse and foot passengers, but not
sufficiently wide for wagons or chaises. Towards this bridge I drove.
The people, not perceiving the structure of my one-wheeled vehicle,
called to me with great eagerness to warn me that the bridge was too
narrow for carriages. I had an excellent horse, which went so fast as to
give but little time for examination. The louder they called, the faster
I drove; and when I had passed the bridge, they shouted after me with
surprise. I got on to Shipstone upon Stone; but before I had dined there
I found that my fame had overtaken me. My carriage was put into a
coach-house, so that those who came from Long Compton, not seeing it,
did not recognize me. I therefore had an opportunity of hearing all the
exaggerations and strange conjectures which were made by those who
related my passage over the narrow bridge. There were posts on the
bridge, to prevent, as I suppose, more than one horseman from passing at
once. Some of the spectators asserted that my carriage had gone over
these posts; others said that it had not wheels, which was indeed
literally true; but they meant to say that it was without any wheel.
Some were sure that no carriage ever went so fast; and all agreed that
at the end of the bridge, where the floods had laid the road for some
way under water, my carriage swam on the surface of the water.
VIII.
JAMES WATT.
"Uncle Fritz," said Mabel Liddell, the next afternoon that our friends
had gathered together for a reading, "would it not be well for us all to
go down into the kitchen this afternoon, and watch the steam come out of
the kettle as Ellen makes tea for us?"
"Why should it be well, Mabel?" said Colonel Ingham. "For my part, I
should prefer to remain in my own room, more especially as I consider my
armchair to be more suited to the comfort of one already on the downward
path in life than is the kitchen table, where we should have to sit
should we invade the premises of our friends below."
"I was thinking," said Mabel, "of the manner in which James Watt when a
child invented the steam-engine, from observing the motion of the top of
the teakettle; and as we are to read about Watt this afternoon I thought
we might be in a more fit condition to understand his invention, and
might more fully comprehend his frame of mind while perfecting his great
work, should we also fix our eyes and minds on the top of the teakettle
in Ellen's kitchen."
"Mabel, my child," said Uncle Fritz, "you talk like a book, and a very
interesting one at that; but I think, as the youngest of us would say,
that you are just a little off in your remarks. And as I observe that
Clem, who is going to read this afternoon, desires to deliver a sermon
of which your conversation seems to be the text, I will request all to
listen to him before we consider seriously vacating this apartment,
however poor it may be,"--and he glanced fondly around at the
comfortable arrangements that everywhere pervaded the study,--"and seek
the regions below."
"I only wanted to say," began Clem, "that although Watt did on one
occasion (in his extreme youth) look at a teakettle with some interest,
he was not in the habit, at the time when he devoted most thought to the
steam-engine, of having a teakettle continually before him that he might
gain inspiration from observing the steam issue from its nose. And, as
Watt dispensed with this aid, I have no doubt that we may do so as well,
contenting ourselves with the results of the experiments in the
vaporization of water, which Ellen is now conducting in the form of tea.
Besides all this, however, I do want to say some things, before we read
aloud this afternoon (I hope this isn't really too much like a sermon),
about the steam-engine and the part that Watt had in perfecting it."
At this point the irrepressible Mabel was heard to whisper to Bedford,
who sat next her: "Wasn't it curious that the same mind which grasped
the immense capabilities of the steam-engine should have been able also
to construct such a delicate lyric as
'How doth the little busy bee
Improve each shining hour'?"
"Mabel," said Colonel Ingham, "you are absolutely unbearable. If you do
not keep in better order I shall be sorry that I dissuaded you from
descending to the kitchen. I see nothing incongruous myself in
indulging in mechanical experiments, and in throwing one's thoughts into
the form of verse,"--here the old gentleman colored slightly, as though
he recollected something of the sort,--"but it may be well to counteract
the impression your conversation may have made by stating that Isaac
Watts did not invent the steam-engine, nor did James Watt write the
beautiful words you have just quoted.--Now, Clem, I believe you have the
floor."
"Well," said Clem, "I only want the floor for a short time in order to
explain about Watt and the steam-engine, and how much he was the
inventor of it, before we begin to read.
"There are various points about the steam-engine which are really Watt's
invention,--the separate condenser, for instance,--but the idea of the
steam-engine was not original with him; that is, when he saw the steam
in the teakettle raise the lid and drop it again, he was not the first
to speculate on the power of steam."
"Are you going to read us that part in the book, Clem?" asked Bedford,
with some interest.
"Yes, if you like," said Clem. "I guess it tells about it in Mr.
Smiles's 'Life of Watt.'" So he began to overhaul the book he had
brought, and shortly discovered the anecdote referred to by Mabel with
such interest, and read it.
"On one occasion he [James Watt] was reproved by Mrs. Muirhead, his
aunt, for his indolence at the tea-table. 'James Watt,' said the worthy
lady, 'I never saw such an idle boy as you are. Take a book, or employ
yourself usefully; for the last hour you have not spoken one word, but
taken off the lid of that kettle and put it on again, holding now a cup
and now a silver spoon over the steam, watching how it rises from the
spout, catching and counting the drops it falls into.' In the view of M.
Arago, the little James before the teakettle, becomes the great
engineer, preparing the discoveries which were soon to immortalize him.
In our opinion, the judgment of the aunt was the truest. There is no
reason to suppose that the mind of the boy was occupied with
philosophical theories on the condensation of steam, which he compassed
with so much difficulty in his maturer years. This is more probably an
afterthought borrowed from his subsequent discoveries. Nothing is
commoner than for children to be amused with such phenomena in the same
way that they will form air-bubbles in a cup of tea, and watch them
sailing over the surface till they burst. The probability is that little
James was quite as idle as he seemed."
"That is very interesting," remarked Mabel. "Don't you think now, Uncle
Fritz, we had better go into the kitchen?" And she looked appealingly at
the old gentleman, who merely held up his finger for silence as Clem
continued his lecture.
"What I meant to say," Clem went on, "was that other people before Watt
had found out the power of steam, and had used it too. There was one
Hero of Alexandria, who lived about two thousand years ago, who used
steam for many interesting purposes, notably for animating various
figures that took part in the idolatrous worship of his time, and thus
in deceiving the common people. But his contrivances, though engines
which went by steam, would hardly be called steam-engines. Between Hero
of Alexandria, of 160 B. C., and the Marquis of Worcester, of 1650 A.
D., there does not seem to have been much doing in the way of inventing
the steam-engine. But the Marquis of Worcester in Charles II.'s time was
a great philosopher, and did nobody knows exactly what with steam. But
though he did great things, he did not produce a particularly capable
engine, though he seems to have known more about steam than anybody else
did at his time. After the Marquis of Worcester and before Watt, there
were three men who did much towards inventing and improving the
steam-engine. Their names were Savery, Papin, and Newcomen. I don't
propose to tell you about the inventions of each one; but it's well
enough to remember that each one did important service in getting the
steam-engine to the point where Watt took hold of it. As it was on
Newcomen's engine that Watt made his first serious experiments, I think
we should all like to know something about it."
THE NEWCOMEN ENGINE.
Newcomen's engine may be thus briefly described: The steam was generated
in a separate boiler, as in Savery's engine, from which it was conveyed
into a vertical cylinder underneath a piston fitting it closely, but
movable upwards and downwards through its whole length. The piston was
fixed to a rod, which was attached by a joint or chain to the end of a
lever vibrating upon an axis, the other end being attached to a rod
working a pump. When the piston in the cylinder was raised, steam was
let into the vacated space through a tube fitted into the top of the
boiler, and mounted with a stopcock. The pump-rod at the further end of
the lever being thus depressed, cold water was applied to the sides of
the cylinder, on which the steam within it was condensed, a vacuum was
produced, and the external air, pressing upon the top of the piston,
forced it down into the empty cylinder. The pump-rod was thereby raised;
and, the operation of depressing it being repeated, a power was thus
produced which kept the pump continuously at work. Such, in a few words,
was the construction and action of Newcomen's first engine.[8]
While the engine was still in its trial state, a curious accident
occurred which led to a change in the mode of condensation, and proved
of essential importance in establishing Newcomen's engine as a practical
working power. The accident was this: in order to keep the cylinder as
free from air as possible, great pains were taken to prevent it passing
down by the side of the piston, which was carefully wrapped with cloth
or leather; and, still further to keep the cylinder air-tight, a
quantity of water was kept constantly on the upper side of the piston.
At one of the early trials the inventors were surprised to see the
engine make several strokes in unusually quick succession; and on
searching for the cause, they found it to consist in _a hole in the
piston_, which had let the cold water in a jet into the inside of the
cylinder, and thereby produced a rapid vacuum by the condensation of the
continued steam. A new light suddenly broke upon Newcomen. The idea of
condensing by injection of cold water directly into the cylinder,
instead of applying it on the outside, at once occurred to him; and he
proceeded to embody the expedient which had thus been accidentally
suggested as part of his machine. The result was the addition of the
injection pipe, through which, when the piston was raised and the
cylinder full of steam, a jet of cold water was thrown in, and, the
steam being suddenly condensed, the piston was at once driven down by
the pressure of the atmosphere.