When James Watt retired from business towards the close of his useful
and admirable life, he spoke to his friends of occupying himself with
"ingenious trifles," and of turning "some of his idle thoughts" upon
the invention of an arithmetical machine and a machine for copying
sculpture. These and other useful works occupied his attention for
many years.
It was the same with myself. I had good health (which Watt had not)
and abundant energy. When I retired from business I was only
forty-eight years old, which may be considered the prime of life.
But I had plenty of hobbies, perhaps the chief of which was Astronomy.
No sooner had I settled at Hammerfield than I had my telescopes brought
out and mounted. The fine clear skies with which we were favoured,
furnished me with abundant opportunities for the use of my instruments.
I began again my investigations on the Sun and the Moon, and made some
original discoveries, of which more anon.
Early in the year 1858 I received a pressing invitation from the
Council of the Edinburgh Philosophical Society to give a lecture before
their members on the Structure of the Lunar Surface. As the subject
was a favourite one with me, and as I had continued my investigations
and increased my store of drawings since I had last appeared before an
Edinburgh audience, I cheerfully complied with their request.
I accordingly gave my lecture before a crowded meeting in the
Queen Street Lecture Hall.
The audience appeared to be so earnestly interested by the subject that
I offered to appear before them on two successive evenings and give any
viva voce explanations about the drawings which those present might
desire. This deviation from the formality of a regular lecture was
attended with the happiest results. Edinburgh always supplies a
highly-intelligent audience, and the cleverest and brightest were ready
with their questions. I was thus enabled to elucidate the lecture and
to expand many of the most interesting points connected with the moon's
surface, such as might formerly have appeared obscure. These questioning
lectures gave the highest satisfaction. They satisfied myself as well
as the audience, who went away filled with the most graphic information
I could give them on the subject.
But not the least interesting part of my visit to Edinburgh on this
occasion was the renewed intercourse which I enjoyed with many of my
old friends. Among these were my venerable friend Professor Pillans,
Charles Maclaren (editor of the Scotsman), and Robert Chambers.
We had a long dander together through the Old Town, our talk being in
broad Scotch. Pillans was one of the fine old Edinburgh Liberals,
who stuck to his principles through good report and through evil.
In his position as Rector of the High School, he had given rare
evidence of his excellence as a classical scholar. He was afterwards
promoted to be a Professor in the University. He had as his pupils
some of the most excellent men of my time. Amongst his intimate
friends were Sydney Smith, Brougham, Jeffrey, Cockburn--men who gave
so special a character to the Edinburgh society of that time.
We had a delightful stroll through some of the most remarkable parts of
the Old Town, with Robert Chambers as our guide. We next mounted
Arthur's Seat to observe some of the manifestations of volcanic action,
which had given such a remarkable structure to the mountain.
On this subject, Charles Maclaren was one of the best living expounders.
He was an admirable geologist, and had closely observed the features of
volcanic action round his native city. Robert Chambers then took us to
see the glacial grooved rocks on another part of the mountain.
On this subject he was a master. It was a vast treat to me to see
those distinct evidences of actions so remotely separated in point of
geological time--in respect to which even a million of years is a
humble approximate unit*
[footnote...
"It is to our ever-dropping climate, with its hundred and fifty-two days
of annual rain, that we owe our vegetable mould with its rich and
beauteous mantle of sward and foliage. And next, stripping from off
the landscape its sands and gravels, we see its underlying boulder-clays,
dingy and gray, and here presenting their vast ice-borne stones,
and there its iceberg pavements. And these clays in turn stripped away,
the bare rocks appear, various in colour and uneven in surface,
but everywhere grooved and polished, from the sea level and beneath it,
to the height of more than a thousand feet, by evidently the same agent
that careered along the pavements and transported the great stones.
HUGH MILLER'S Geological Features of Edinburgh and its Neighbourhood.
...]
What a fine subject for a picture the group would have made! with the
great volcanic summit of the mountain behind, the noble romantic city
in the near distance, and the animated intelligent countenaces of the
demonstrators, with the venerable Pillans eagerly listening--for the
Professor was then in his eighty-eighth year. I had the happiness of
receiving a visit from him at Hammerfield in the following year.
He was still hale and active; and although I was comparatively a boy to
him, he was as bright and clear-headed as he had been forty years before.
In the course of the same year I accompanied my wife and my sister
Charlotte on a visit to the Continent. It was their first sojourn in
foreign parts. I was able, in some respects, to act as their guide.
Our visit to Paris was most agreeable. During the three weeks we were
there, we visited the Louvre, the Luxembourg, Versailles, and the parts
round about. We made many visits to the Hotel Cluny, and inspected its
most interesting contents, as well as the Roman baths and that part of
the building devoted to Roman antiquities. We were especially
delighted with the apartments of the Archbishop of Paris, now hung with
fine old tapestry and provided with authentic specimens of mediaeval
furniture. The quaint old cabinets were beautiful studies; and many
artists were at work painting them in oil. Everything was in harmony.
When the sun shone in through the windows in long beams of coloured
light, illuminating portions of the antique furniture, the pictures
were perfect. We were much interested also by the chapel in which
Mary Queen of Scots was married to the Dauphin. It is still in complete
preservation. The Gothic details of the chapel are quite a study;
and the whole of these and the contents of this interesting Museum form
a school of art of the best kind.
From Paris we paid a visit to Chartres, which contains one of the most
magnificent cathedrals in France. Its dimensions are vast,
its proportions are elegant, and its painted glass is unequalled.
Nothing can be more beautiful than its three rose-windows. But I am
not writing a guide-book, and I must forbear. After a few days more at
Paris we proceeded south, and visited Lyons, Avignon, and Nismes, on
our way to Marseilles. I have already described Nismes in my previous
visit to France. I revisited the Roman amphitheatre, the Maison Quarree,
that perfect Roman temple, which, standing as it does in an open
square, is seen to full advantage. We also went to see the magnificent
Roman aqueduct at Pont du Gard. The sight of the noble structure well
repays a visit. It consists of three tiers of arches. Its magnitude,
the skilful fitting of its enormous blocks, makes a powerful impression
on the mind. It has stood there, in that solitary wooded valley,
for upwards of sixteen centuries; and it is still as well fitted for
conveying its aqueduct of water as ever. I have seen nothing to
compare with it, even at Rome. It throws all our architectural buildings
into the shade. On our way back from Marseilles to Paris we visited
Grenoble and its surrounding beautiful Alpine scenery.
Then to Chambery, and afterwards to Chamounix, where we obtained a
splendid view of Mont Blanc. We returned home by way of Geneva and
Paris, vastly delighted with our most enjoyable journey.
I return to another of my hobbies. I had an earnest desire to acquire
the art and mystery of practical photography. I bought the necessary
apparatus, together with the chemicals; and before long I became an
expert in the use of the positive and negative collodion process,
including the printing from negatives, in all the details of that
wonderful and delightful art. To any one who has some artistic taste,
photography, both in its interesting processes and glorious results,
becomes a most attractive and almost engrossing pursuit. It is a
delightful means of educating the eye for artistic feeling, as well as
of educating the hands in delicate manipulation. I know of nothing
equal to photography as a means of advancing one's knowledge in these
respects. I had long meditated a work "On the Moon," and it was for
this purpose more especially that I was earnest in endeavouring to
acquire the necessary practical skill. I was soon enabled to obtain
photographic copies of the elaborate models of parts of the moon's,
surface, which I had long before prepared. These copies were hailed by
the highest authorities in this special department of astronomical
research as the best examples of the moon's surface which had yet been
produced.
In reference to this subject, as well as to my researches into the
structure of the sun's surface, I had the inestimable happiness of
securing the friendship of that noble philosopher, Sir John Herschel.
His visits to me, and my visits to him, have left in my memory the most
cherished and happy recollections. Of all the scientific men I have
had the happiness of meeting, Sir John stands supremely at the head of
the list. He combined profound knowledge with perfect humility.
He was simple, earnest, and companionable, He was entirely free from
assumptions of superiority, and, still learning, would listen
attentively to the humblest student. He was ready to counsel and
instruct, as well as to receive information. He would sit down in my
workshop, and see me go through the various technical processes of
casting, grinding, and polishing specula for reflecting telescopes.
That was a pleasure to him, and a vast treat to me.
I had been busily occupied for some time in making careful investigations
into the dark spots upon the Sun's surface. These spots are of
extraordinary dimensions, sometimes more than 10,000 miles in diameter.
Our world might be dropped into them. I observed that the spots were
sometimes bridged over by a streak of light, formed of
willow-leaf-shaped objects. They were apparently possessed of
voluntary motion, and moved from one side of the spot to the other.
These flakes were evidently the immediate sources of the solar light
and heat. I wrote a paper on the subject, which I sent to the Literary
and Philosophical Society of Manchester.*
[footnote...
Memoirs of the Literary and Philosophical Society of Manchester,
3d series, vol. i. p. 407. My first discovery of the "Willow-leaf"
objects on the Sun's surface was made in June 1860.I afterwards
obtained several glimpses of them from time to time.But the occasions
are very rare when the bright sun can be seen in a tranquil atmosphere
free from vibrations, and when the delicate objects on its surface can
be clearly defined. It was not until the 5th of June 1864 that I
obtained the finest sight of the Sun's spots and the Willow-leaf objects;
it was then that I made a careful drawing of them, from which the
annexed faithful engraving has been produced. Indeed I never had a
better sight of this extraordinary aspect of the Sun than on that day.
...]
The results of my observations were of so novel a character that
astronomers for some time hesitated to accept them as facts.
Yet Sir John Herschel, the chief of astronomers, declared them to be
"a most wonderful discovery"
[Image] Group of sun spots as seen by James Nasmyth, 5th June 1864.
I received a letter from Sir John, dated Collingwood, 2lst of May 1861,
in which he said:
"I am very much obliged to you for your note, and by the sight of your
drawings, which Mr. Maclaren was so kind as to bring over here the
other day. I suppose there can be no doubt as to the reality of the
willow-leaved flakes, and in that case they certainly are the most
marvellous phenomena that have yet turned up--had almost said in all
Nature--certainly in all Astronomy.
"What can they be? Are they huge phosphorised fishes? If so, what
monsters! Or are they crystals? a kind of igneous snow-flakes?
floating in a fluid of their own, or very nearly their own, specific
gravity? Some kind of solidity or coherence they must have, or they
would not retain their shape in the violent movements of the atmosphere
which the change of the spots indicate.
"I observe that in the bridges all their axes have an approximate
parallelism, and that in the penumbra they are dispersed, radiating
from the inside and the outside of the spot, giving rise to that
striated appearance which is familiar to all observers of the spots.
"I am very glad that you have pitched your tent in this part of the
world, and I only wish it were a little nearer. You will anyhow have
the advantage at Penshurst of a much clearer atmosphere than in the
north; but here, nearer the coast, I think we are still better off.
"Mr. Maclaren holds out the prospect of our meeting you at Pachley at
no distant period, and I hope you will find your way ere long to
Collingwood. I have no instruments or astronomical apparatus to show
you, but a remarkably pretty country, which is beginning to put on
(rather late) its gala dress of spring?'
Sir John afterwards requested my permission to insert in his
Outlines of Astronomy, of which a new edition was about to appear, a
representation of "the willow-leaved structure of the Sun's surface,"
--which had been published in the Manchester transactions,--to which
I gladly gave my assent. Sir John thus expresses himself on the
subject: --"The curious appearance of the 'pores' of the Sun's surface
has lately received a most singular and unexpected interpretation from
the remarkable discovery of Mr. J. Nasmyth, who, from a series of
observations made with a reflecting telescope of his own construction
under very high magnifying powers, and under exceptional circumstances
of tranquillity and definition, has come to the conclusion that these
pores are the polygonal interstices between certain luminous objects of
an exceedingly definite shape and general uniformity of size,
whose form (at least as seen in projection in the central portions of
the disc) is that of the oblong leaves of a willow tree. These cover
the whole disc of the Sun (except in the space occupied by spots) in
countless millions, and lie crossing each other in every imaginable
direction.... This most astonishing revelation has been confirmed to a
certain considerable extent, and with some modifications as to the form
of the objects, their exact uniformity of size and resemblance of
figure, by Messrs. De la Rue, Pritchard and Stone in England,
and M. Secchi in Rome."
On the 25th of February 1864, I received a communication from
Mr. E. J. Stone, first assistant at the Royal Observatory, Greenwich.
The Astronomer-Royal, he said, "has placed in my hands your letter of
February 20. Your discovery of the 'willow leaves' on the Solar
photosphere having been brought forward at one of the late meetings of
the Royal Astronomical Society, my attention was attracted to the
subject. At my request, the Astronomer-Royal ordered of Mr. J. Simms a
reflecting eye-piece for our great equatorial. The eye-piece was
completed about the end of January last, and at the first good
opportunity I turned the telescope on the Sun.
"I may state that my impression was, and it appears to have been the
impression of several of the assistants here, that the willow leaves
stand out dark against the luminous photosphere. On looking at the
Sun, I was at once struck with the apparent resolvability of its
mottled appearance. The whole disc of the Sun, so far as I examined
it, appeared to be covered over with relatively bright rice-like
particles, and the mottled appearance seemed to be produced by the
interlacing of these particles.
"I could not observe any particular arrangement of the particles, but
they appeared to be more numerous in some parts than in others.
I have used the word 'rice-like' merely to convey a rough impression of
their form. I have seen them on two occasions since, but not so well
as on the first day, when the definition was exceedingly good.
"on the first day that I saw them I called Mr Dunkin's attention to
them. He appears to have seen them. He says, however, that he should
not have noticed them if his attention had not been called to them."
The Astronomer Royal, in his report to the Admiralty on my discovery,
said:
"an examination of the Sun's surface with the South-East Equatorial,
under favourable circumstances, has convinced me of the accuracy of the
description, which compares it with interlacing willow leaves or rice
grains."
In March 1864 I received a letter from my friend De la Rue, dated from
his observatory at Cranford, Middlesex, in which he said: "I like good
honest doubting. Before I had seen with my own eyes your willow
leaves, I doubted their real existence, but I did not doubt your having
seen what you had drawn. But when I actually saw them for the first
time, I could not restrain the exclamation, ' Why, here are Nasmyth's
willow leaves! ' It requires a very fine state of the atmosphere to
permit of their being seen, as I have seen them on three or four
occasions, when their substantial reality can no longer be doubted."*
[footnote...
Let me give another letter from my friend, dated the Observatory,
Cranford, Middlesex, October 26, 1864. He said:-
"I am quite pleased to learn that you like the large photograph.
The first given to my friend was destined for and sent to you.
No one has so great a claim on the fruit of my labours; for you
inoculated me with the love of star-gazing, and gave me invaluable aid
and advice in figuring specula. I daresay you may remember the first
occasion on which I saw a reflecting telescope, which was then being
tried on the sun in a pattern loft at Patricroft. You may also recall
the volumes you wrote in answer to my troublesome questions.
Yours very sincerely WARREN DE LA RUE."
...]
Sir John Herschel confirmed this information in a letter which I
received from him in the following May. He said "that Mr. De la Rue
and a foreign gentleman, Hugo Muller, had been very successful in
seeing and delineating the 'willow leaves' They are represented by
Mr. M. as packed together on the edge of a spot, and appear rather like
a bunch of bristles or thorns. In other respects the individual forms
agree very well with your delineations." Another observer had
discovered a marvellous resemblance between the solar spots and the
hollows left by the breaking and subsidence of bubbles, which rise when
oil varnish, which has moisture in it, is boiled, and the streaky
channels are left by the retiring liquid. "I cannot help," adds
Sir John, "fancying a bare possibility of some upward outbreak,
followed by a retreat of some gaseous matter, or some dilated portion
of the general atmosphere struggling upwards, and at the same time
expanding outwards. I can conceive of an up-surge of some highly
compressed matter, which relieved of pressure, will dilate laterally
and upwards to an enormous extent (as Poullett Scrope supposes of his
lavas full of compressed gases and steam), producing the spots, and,
in that case, the furrows might equally well arise in the origination
as in the closing in of a spot."
I had the honour and happiness of receiving a visit from Sir John
Herschel at my house at Hammerfield in the summer of 1864.
He was accompanied by his daughter. They spent several days with us.
The weather was most enjoyable. I had much conversation with Sir John
as to the Sun spots and willow-leaf-shaped objects on the Sun's
surface, as well as about my drawings of the Moon. I exhibited to him
my apparatus for obtaining sound castings of specula for reflecting
telescopes. I compounded the alloy, melted it, and cast a 10-inch
speculum on my peculiar common-sense system. I introduced the molten
alloy, chilled it in a metal mould, by which every chance of flaws and
imperfections is obviated. I also showed him the action and results of
my machine, by which I obtained the most exquisite polish and figure
for the speculum. Sir John was in the highest degree cognisant of the
importance of these details, as contributing to the final excellent
result. It was therefore with great pleasure that I could exhibit
these practical details before so competent a judge.
We had a great set-to one day in blowing iridescent soap bubbles from a
mixture of soap and glycerine. Some of the bubbles were of about
fifteen inches diameter. By carefully covering them with a bell glass,
we kept them for about thirty-six hours, while they went through their
changes of brilliant colour, ending in deep blue. I contrived this
method of preserving them by placing a dish of water below, within the
covering bell glass, by means of which the dampness of the air
prevented evaporation of the bubble. This dodge of mine vastly
delighted Sir John, as it allowed him to watch the exquisite series of
iridescent tints at his tranquil leisure.
[Image] From a photograph of the Moon, exhibiting the bright radial
lines.
[Image] Glass globe cracked by internal pressure, in illustration of
the cause of the bright radial lines seen on the moon.
I had also the pleasure of showing him my experiment of cracking a
glass globe filled with water and hermetically sealed. The water was
then slightly expanded, on which the glass cracked. This was my method
of explaining the nature of the action which, at some previous period
of the cosmical history of the Moon, had produced those bright
radiating lines that diverge from the lunar volcanic craters.
Sir John expressed his delight at witnessing my practical illustration
of this hitherto unexplained subject, and he considered it quite
conclusive. I also produced my enlarged drawings of the Moon's
surface, which I had made at the side of my telescope. These greatly
pleased him and he earnestly urged me to publish them, accompanied with
a descriptive account of the conclusions I had arrived at.
I then determined to proceed with the preparations which I had already
made for my long contemplated work.
Among the many things that I showed Sir John while at Hammerfield, was
a piece of white calico on which I had got printed one million spots.
[footnote...
At a recent meeting of the Metropolitan Railway Company
I exhibited one million of letters, in order to show the number of
passengers (thirty-seven millions) that had been conveyed during the
previous twelve months. This number was so vast that my method only
helped the meeting to understand what had been done in the way of
conveyance. Mr. Macdonald of the Times, supplied me with one million
type impressions, contained in sixty average columns of the Times
newspaper.
...]
This was for the purpose of exhibiting one million in visible form.
In astronomical subjects a million is a sort of unit, and it occurred
to me to show what a million really is. Sir John was delighted and
astonished at the sight. He went carefully over the outstretched piece
with his rule, measured its length and breath, and verified its
correctness.
I also exhibited to him a diagram, which I had distributed amongst the
geologists at the meeting of the British Association at Ipswich in
1851, showing a portion of the earth's curve, to the scale of one-tenth
of an inch to a mile. I set out the height of Mont Blanc, Etna, and
also the depth of the deepest mine, as showing the almost incredible
minimum of knowledge we possess about even the merest surface of the
globe. This diagram was hailed by many as of much value, as conveying
a correct idea of the relative magnitude of geological phenomena in
comparison with that of the earth itself:
On this subject Sir Thomas Mitchell, Surveyor-General of Australia,
wrote to me at the time: "I will not obtrude upon you my crude notions
of my own, but merely say that you could not have sent the 'Geological
Standard Scale' to one who better deserved it, if the claim in such
favour is, as I suppose, to be estimated by the amount of the time of
one whole life, applied to the survey of great mountain ranges, and
coasts, rivers, etc. By this long practice of mine, you may know how
appreciable this satisfactory standard scale is to your humble servant.
In the winter of 1865 I visited Italy. While at Rome, in April, I had
the pleasure of meeting Otto W. von Struve, the celebrated Russian
astronomer. He invited me to accompany him on a visit to Father Secchi
at his fine observatory of the Collegio Romano. I accepted the
invitation with pleasure. We duly reached the Observatory when Struve
introduced me to the Father. Secchi gave me a most cordial and
unlooked-for welcome. "This," he said, "is a most extraordinary
interview; as I am at this moment making a representation of your
willow-leaf-shaped constituents of the Solar surface!" He then pointed
to a large black board, which he had daubed over with glue and was
sprinkling over ( when we came in) with rice grains "That," said he,
"is what I feel to be a most excellent representation of your discovery
as I see it, verified by the aid of my telescope." It appeared to
Father Secchi so singular a circumstance that I should come upon him in
this sudden manner, while he was for the first time engaged in
representing what I had (on the spur of the moment when first seeing
them) described as willow-leaf-shaped objects. I thought that his
representation of them, by scattering rice grains over his glue-covered
black board, was apt and admirable; and so did Otto Struve.
This chance meeting with these two admirable astronomers was one of the
little bits of romance in my life.
I returned to England shortly after. Among our visitors at Hammerfield
was Lord Lyndhurst. He was in his ninetieth year when he paid a visit
to Tunbridge Wells. Charles Greville, Secretary to the Privy Council,
wrote to me, saying that his Lordship complained much of the want of
society, and asked me to call upon him. I did so, and found him
cheerful and happy.
I afterwards sent him a present of some of my drawings. He answered:
"A thousand thanks for the charming etchings. I am especially
interested in Robinson Crusoe. He looks very comfortable, but I can't
see his bed, which troubles me. The election ('Everybody for ever!')
is wonderful. I should not like to be there. I hope we shall go to
you again one of these days, and have another peep into that wonderful
telescope."
To return to Sir John Herschel, We returned his visit at his house at
Collingwood, near Hawkhurst. I found him in the garden, down upon his
knees, collecting crocus bulbs for next year's planting. Like myself,
he loved gardening, and was never tired of it. I mention this as an
instance of his simple zeal in entering practically into all that
interested him. At home he was the happy father and lover of his
family. One of his favourite pastimes, when surrounded by his children
in the evening, was telling them stories. He was most happy and
entertaining in this tranquil occupation. His masterly intellect could
grasp the world and all its visible contents, and yet descend to
entertain his children with extemporised tales. He possessed
information of the most varied kind, which he communicated with perfect
simplicity and artlessness! His profound astronomical knowledge was
combined with a rich store of mechanical and manipulative faculty,
which enabled him to take a keen interest in all the technical arts
which so materially aid in the progress of science. I shall never
forget the happy days that he spent with me in my workshop. His visits
have left in my mind the most cherished recollections. Our friendly
intercourse continued unbroken to the day of his death. The following
is the last letter I received from him:
COLLINGWOOD, March 10, 1871.
"MY DEAR SIR--A great many thanks for the opportunity of seeing your
most exquisite photographs from models of lunar mountains. I hope you
will publish them. They will create quite an electric sensation.
Would not one or two specimens of the apparently nonvolcanic mountain
ranges, bordering on the great plains, add to the interest? Excuse my
writing more, as I pen this lying on my back in bed, to which a fierce
attack of bronchitis condemns me. With best regards to Mrs. Nasmyth,
believe me yours very truly,
" J. F. W. HERSCHEL."
Scientific knowledge seems to travel slowly, It was not until the year
1875, more than fourteen years after my discovery of the willow-leaved
bridges over the Sun's spots that I understood they had been accepted
in America. I learned this from my dear friend William Lassell.
His letter was as follows: --"I see the Americans are appreciating
your solar observations. A communication I have lately received from
the Alleghany Observatory remarks 'that he (Mr. Nasmyth) appears to
have been the first to distinctly call attention to the singular
individuality of the minute components of the photosphere; and this
seems in fairness to entitle him to the credit of an important
discovery, with which his name should remain associated.'"
I proceeded to do that which Sir John Herschel had so earnestly
recommended, that is, to write out my observations on the Moon.
It was a very serious matter, for I had never written a book before.
It occupied me many years, though I had the kind assistance of my
friend James Carpenter, then of the Royal Observatory, Greenwich.
The volcanoes and craters, and general landscape scenery of the Moon,
had to be photographed and engraved, and this caused great labour.
At length the book, entitled The Moon, considered as a Planet, a World,
and a Satellite, appeared in November 1874. It was received with much
favour and passed into a second edition. A courteous and kind review
of the book appeared in the Edinburgh; and the notices in other
periodicals were equally favourable. I dedicated the volume to the
Duke of Argyll, because I had been so long associated with him in
geological affairs, and also because of the deep friendship which I
entertained for his Grace. I presented the volume to him as well as to
many other of my astronomical friends. I might quote their answers at
great length, from the Astronomer-Royal downwards. But I will quote
two--one from a Royal Academician and another from a Cardinal.
The first was from Philip H. Calderon. He said:
"Let me thank you many times for your kind letter, and for your
glorious book. It arrived at twelve to-day, and there has been no
painting since. Once having taken it up, attracted by the
illustrations, I could not put it down again. I forgot everything;
and, indeed, I have been up in the Moon. As soon as these few words of
thanks are given, I am going up into the Moon again. What a comfort it
is to read a scientific work which is quite clear, and what a gift it
is to write thus!
"The photographs took my breath away. I could not understand how you
did them, and your explanation of how you built the models from your
drawings only changed the wonder into admiration. Only an artist could
have said what you say about the education of the eye and of the hand.
You may well understand how it went home to me. Ever gratefully yours,
PHILIP H. CALDERON."
I now proceed to the Cardinal. I was present at one of the receptions
of the President of the Royal Society at Burlington House, when I was
introduced to Cardinal Manning as "The Steam Hammer!" After a cordial
reception he suddenly said, "But are you not also the Man in the Moon?"
Yes, your Eminence. I have written a book about the Moon, and I shall
be glad if you will accept a copy of it?" "By all means," he said,
"and I thank you for the offer very much." I accordingly sent the copy,
and received the following answer:
"MY DEAR MR.NASMYTH--When I asked you to send me your book on the
Moon, I had no idea of its bulk and value, and I feel ashamed of my
importunity, yet more than half delighted at my sturdy begging.
"I thank you for it very sincerely. My life is one of endless work,
leaving me few moments for reading. But such books as yours refresh me
like a clover field.
"I hope I may have an opportunity of renewing our conversation.
Believe me always truly yours, HENRY, CARDINAL MANNING."
I may also mention that I received a charming letter from Miss Herschel,
the daughter of the late Astronomer.
"Is it possible," she said, "that this beautiful book is destined by
you as a gift to my most unworthy self? I do not know, indeed, how
sufficiently to thank you, or even to express my delight in being
possessed of so exquisite and valuable a work, made so valuable, too,
by the most kind inscription on the first page! I fear I shall be very
very far from understanding the theories developed in the book, though
we have been endeavouring to gather some faint notion of them from the
reviews we have seen; but it will be of the greatest interest for us to
try and follow them under your guidance, and with the help of these
perfectly enchanting photographs, which, I think, one could never be
tired of looking at.
"How well I remember the original photographs, and the oil painting
which you sent for dear papa's inspection, and which he did so enjoy!
and also the experiment with the glass globe, in which he was so
interested, at your own house. We cannot but think how he would have
appreciated your researches, and what pleasure this lovely book would
have given him. Indeed, I shall treasure it especially as a
remembrance of that visit, which is so completely connected in my
thoughts with him, as well as with your cordial kindness, as a precious
souvenir, of which let me once more offer you my heartfelt thanks.
I remain, my dear sir, yours very truly and gratefully,
"ISABELLA HERSCHEL."
I cannot refrain from adding the communication I received from my dear
old friend William Lassell. "I do not know," he said,
"how sufficiently to thank you for your most kind letter, and the
superb present which almost immediately followed it. My pleasure was
greatly enhanced by the consideration of how far this splendid work
must add to your fame and gratify the scientific world.
The illustrations are magnificent, and I am persuaded that no book has
ever been published before which gives so faithful, accurate,
and comprehensive a picture of the surface of the Moon. The work must
have cost you much time, thought, and labour, and I doubt not you will
now receive a gratifying, if not an adequate reward."
After reading the book Mr. Lassell again wrote to me. "I am indebted
to your beautiful book, "he said, "for a deeper interest in the Moon
than I ever felt before.... I see many of your pictures have been
taken when the Moon was waning, which tells me of many a shivering
exposure you must have had in the early mornings,... I was sorry to
find from your letter that you had a severe cold, which made you very
unwell. I hope you have ere this perfectly recovered. I suppose
maladies of this kind must be expected to take rather severe hold of us
now, as we are both past the meridian of life. I am, however,
very thankful for the measure of health I enjoy, and the pleasure
mechanical pursuits give me. I fully sympathise with you in the
contempt (shall I say?) which you feel for the taste of so many people
who find their chief pleasure in 'killing something,' and how often
their pleasures are fatal! Two distinguished men killed only the other
day in hunting. For my part I would rather take to the bicycle and do
my seventeen miles within the hour."
He proceeds: "I have no doubt your windmill is very nicely contrived,
and has afforded you much pleasure in constructing it.
The only drawback to it is, that in this variable climate it is apt to
strike work, and in the midst of a job of polishing I fear no increase
of wages would induce it to complete its task! If water were plentiful,
you might make it pump up a quantity when the wind served, to be used
as a motive power when you chose."
This reference alludes to a windmill which I erected on the top of my
workshop, to drive the apparatus below. It was the mirror of a
reflecting telescope which was in progress. The windmill went on night
and day, and polished the speculum while I slept. In the small hours
of the morning I keeked through the corner of the window blinds and saw
it hard at work. I prefer, however, a small steam-engine, which works
much more regularly.
It is time to come to an end of my Recollections. I have endeavoured
to give a brief resume of my life and labours. I hope they may prove
interesting as well as useful to others. Thanks to a good constitution
and a frame invigorated by work, I continue to lead, with my dear wife,
a happy life. I still take a deep interest in mechanics, in astronomy,
and in art. It is a pleasure to me to run up to London and enjoy the
collections at the National Gallery, South Kensington, and the Royal
Academy. The Crystal Palace continues to attract a share of my
attention, though, since the fire, it has been greatly altered.
I miss, too, many of the dear accustomed faces of the old friends we
used to meet there. Still we visit it, and leave to memory the filling
up of what is gone. All things change, and we with them.
The following Dial of Life gives a brief summary of my career.
It shows the brevity of life, and indicates the tale that is soon told.
The first part of the semicircle includes the passage from infancy to
boyhood and manhood. While that period lasts, time seems to pass very
slowly. We long to be men, and doing men's work. What I have called
The Tableland of Life is then reached. Ordinary observation shows that
between thirty and fifty the full strength of body and mind is reached;
and at that period we energise our faculties to the utmost.
[Image] The Dial of Life
Those who are blessed with good health and a sound constitution may
prolong the period of energy to sixty or even seventy; but Nature's
laws must be obeyed, and the period of decline begins, and goes on with
accelerated rapidity. Then comes Old Age; and as we descend the
semicircle towards eighty, we find that the remnant of life becomes
vague and cloudy. By shading off, as I have done, the portion of the
area of the diagram according to the individual age, every one may see
how much of life is consumed, and what is left--D.V.. Here is my
brief record:
AGE YEAR.
-- 1808. BORN 19TH AUGUST.
9 1817. WENT TO THE HIGH SCHOOL, EDINBURGH.
13 1821. ATTENDED THE SCHOOL OF ARTS.
21 1829. WENT TO LONDON, TO MAUDSLAY'S.
23 1831. RETURNED TO EDINBURGH, TO MAKE MY ENGINEERS' TOOLS.
26 1834. WENT TO MANCHESTER, TO BEGIN BUSINESS.
28 1836. REMOVED TO PATRICROFT, AND BUILT THE BRIDGEWATER FOUNDRY.
31 1839. INVENTED THE STEAM HAMMER.
32 1840. MARRIAGE.
34 1842. FIRST VISIT TO FRANCE AND ITALY.
35 1843. VISIT TO ST. PETERSBURG, STOCKHOLM, DANNEMORA.
37 1845. APPLICATION OF THE STEAM HAMMER TO PILE-DRIVING.
48 1856. RETIRED FROM BUSINESS, TO ENJOY THE REST OF MY LIFE IN THE
ACTIVE PURSUIT OF MY MOST FAVOURITE OCCUPATIONS.
I have not in this list referred to my investigations in connection
with astronomy. All this will be found referred to in the text.
It only remains for me to say that I append a resume of my inventions,
contrivances, and workshop "dodges," to give the reader a summary idea
of the Active Life of a working mechanic. And with this I end my tale.
CHRONOLOGICAL LIST OF MECHANICAL INVENTIONS AND TECHNICAL CONTRIVANCES.
by James Nasmyth.
1825. A mode of applying Steam Power for the Traction of Canal Barges,
without injury to the Canal Banks.
A CANAL having been formed to connect Edinburgh with the Forth and
Clyde Canal, and so to give a direct waterway communication between
Edinburgh and Glasgow, I heard much talk about the desirableness of
substituting Steam for Horse power as the means of moving the boats and
barges along the canal. But, as the action of paddle wheels had been
found destructive to the canal banks, no scheme of that nature could be
entertained. Although a tyro in such matters, I made an attempt to
solve the problem, and accordingly prepared drawings, with a
description of my design, for employing Steam power as the tractive
agency for trains of canal barges, in such a manner as to obviate all
risk of injury to the banks.
[Image]
The scheme consisted in laying a chain along the bottom of the canal,
and of passing any part of its length between three grooved and notched
pulleys or rollers, made to revolve with suitable velocity by means of
a small steam-engine placed in a tug-boat, to the stern of which a
train of barges was attached.*
[footnote...
Had this simple means of "tugging" vessels through water-ways been
employed in our late attempts to ascend the rapids of the Nile, some
very important results might have issued from its adoption.
...]
The steam-engine could thus warp its way along the chain, taking it up
between the rollers of the bow of the tug-boat, and dropping it into
the water at the stern, so as to leave the chain at the service of the
next following tug-boat with its attached train of barges. By this
simple mode of employing the power of a steam-engine for canal boat
traction, all risk of injury to the banks would be avoided, as the
chain and not the water of the canal was the fulcrum or resistance
which the steam-engine on the tug-boat operated upon in thus warping
its way along the chain; and thus effectually, without slip or other
waste of power, dragging along the train of barges attached to the
stern of the steam-tug. I had arranged for two separate chains,
so as to allow trains of barges to be conveyed along the canal in
opposite directions, without interfering with each other.
I submitted a complete set of drawings, and a full description of my
design in all its details, to the directors of the Canal Company;
and I received a complimentary acknowledgment of them in writing. But
such was the prejudice that existed, in consequence of the injury to
the canal banks resulting from the use of paddle Wheels, that it
extended to the use of steam power in any form, as a substitute for
ordinary horse traction; and although I had taken every care to point
out the essential difference of my system (as above indicated) by which
all such objections were obviated, my design was at length courteously
declined, and the old system of horse traction continued.
In 1845 I had the pleasure to see this simple mode of moving vessels
along a definite course in most successful action at the ferry across
the Hamoaze at Devonport, in which my system of employing the power of
a steam-engine on board the ferry boat, to warp its way along a
submerged chain lying along the bottom of the channel from side to side
of the ferry, was most ably carried out by my late excellent friend,
James Rendell, Esq., C.E., and is still, I believe, in daily action,
giving every satisfaction.
1826. An Instrument for Measuring the Total and Comparative Expansion
of all Solid Bodies.
My kind friend and patron, Professor Leslie, being engaged in some
investigations in which it was essential to know the exact comparative
total expansion in bulk of metals and other solid bodies, under the
same number of degrees of heat, mentioned the subject in the course of
conversation. The instrument at that time in use was defective in
principle as well as in construction, and the results of its
application were untrustworthy. As the Professor had done me the honour
to request me to assist him in his experiments, I had the happiness to
suggest an arrangement of apparatus which I thought might obviate the
sources of error; and, with his approval, I proceeded to put it in
operation.
My contrivance consisted of an arrangement by means of which the metal
bar or other solid substance, whose total expansion under a given
number of degrees of heat had to be measured, was in a manner itself
converted into a thermometer. Absolutely equal bulks of each solid were
placed inside a metal tube or vessel, and surrounded with an exact
equal quantity of water at one and the same normal temperature.
A cap or cover, having a suitable length of thermometer tube attached
to it, was then screwed down, and the water of the index tube was
adjusted to the zero point of the scale attached to it, the whole being
at say 50deg of heat, as the normal temperature in each case. The
apparatus was then heated up to say 200deg by immersion in water at
that temperature. The expansion of the enclosed bar of metal or other
solid substance under experiment caused the water to rise above the
zero, and it was accordingly so indicated on the scale attached to the
cap tube. In this way we had a thermometer whose bulb was for the time
being filled with the solid under investigation,--the water surrounding
it imply acting as the means by which the expansion of each solid under
trial was rendered visible, and its amount capable of being ascertained
and recorded with the utmost exactness, as the expansion of the water
was in every case the same, and also that of the instrument itself
which was "a constant quantity."
In this way we obtained the correct relative amount of expansion in
bulk of all the solid substances experimented upon. That each bar of
metal or other solid substance was of absolutely equal bulk, was
readily ascertained by finding that each, when weighed in water,
lost the exact same weight.
[Image] James Nasmyth's Expansometer, 1826.
My friend, Sir David Brewster, was so much pleased with the instrument
that he published a drawing and description of it in the Edinburgh
Philosophical Journal, of which he was then editor.
1827. A Method of increasing the Effectiveness of Steam by
super-heating it on its Passage from the Boiler to the Engine.
One or the earliest mechanical contrivances which I made was for
preventing water, in a liquid form, from passing along with the steam
from the boiler to the cylinder of the steam-engine.
The first steam-engine I made was employed in grinding oil colours for
my father's use in his paintings. When I set this engine to work for
the first time I was annoyed by slight jerks which now and then
disturbed the otherwise smooth and regular action of the machine.
After careful examination I found that these jerks were caused by the
small quantities of water that were occasionally carried along with the
current of the steam, and deposited in the cylinder, where it
accumulated above and below the piston, and thus produced the jerks.
In order to remove the cause of these irregularities, I placed a
considerable portion of the length of the pipe which conveyed the steam
from the boiler to the engine within the highly heated side flue of the
boiler, so that any portion of water in the liquid form which might
chance to pass along with the steam, might, ere it reached the
cylinder, traverse this highly-heated steam pipe, and, in doing so,
be converted into perfectly dry steam, and in that condition enter the
cylinder. On carrying this simple arrangement into practice, I found
the result to be in every way satisfactory. The active little
steam-engine thence-forward performed its work in the most smooth and
regular manner.
So far as I am aware, this early effort of mine at mechanical
contrivance was the first introduction of what has since been termed
"super-heated steam"--a system now extensively employed, and yielding
important results, especially in the case of marine steam-engines.
Without such means of supplying dry steam to the engines, the latter
are specially liable to "break-downs," resulting from water,
in the liquid form, passing into the cylinders along with the steam.
1828. A Method of "chucking" delicate Metal-work, in order that it may
be turned with perfect truth
In fixing portions of work in the turning-lathe, one of the most
important points to attend to is, that while they are held with
sufficient firmness in order to be turned to the required form, they
should be free from any strain which might in any way distort them.
In strong and ponderous objects this can be easily accomplished by due
care on the part of an intelligent workman. It is in operating by the
lathe on delicate and flexible objects that the utmost care is
requisite in the process of chucking, as they are easily strained out
of shape by fastening them by screws and bolts, or suchlike ordinary
means. This is especially the case with disc-like objects. As I had on
several occasions to operate in the lathe with this class of work I
contrived a method of chucking or holding them firm while receiving the
required turning process, which has in all cases proved most handy and
satisfactory.
This method consisted of tinning three, or, if need be, more parts of
the work, and laying them down on a tinned face-plate or chuck,
which had been heated so as just to cause the solder to flow. As soon
as the solder is cooled and set, the chuck with its attached work may
then be put in the lathe, and the work proceeded with until it is
completed. By again heating the chuck, by laying upon it a piece of
red-hot iron, the work, however delicate, can be simply lifted off,
and will be found perfectly free from all distortion.
I have been the more particular in naming the use of three points of
attachment to the chuck or face-plate, as that number is naturally free
from any risk of distortion. I have on so many occasions found the
great value of this simple yet most secure mode of fixing delicate work
in the lathe, that I feel sure that any one able to appreciate its
practical value will be highly pleased with the results of its
employment.
The same means can, in many cases, be employed in fixing delicate work
in the planing-machine. All that is requisite is to have a clean-planed
wrought-iron or brass fixing-plate, to which the work in hand can be
attached at a few suitable parts with soft solder, as in the case of
the turning lathe above described.
1828. A Method of casting Specula for Reflecting Telescopes, so as to
ensure perfect Freeness from Defects, at the same time enhancing
the Brilliancy of the Alloy.
My father possessed a very excellent achromatic spy-glass of 2 inches
diameter. The object-glass was made by the celebrated Ramsden.
When I was about fifteen I used it to gaze at the moon, planets, and
sun-spots. Although this instrument revealed to me the general
characteristic details of these grand objects, my father gave me a
wonderful account of what he had seen of the moon's surface by means of
a powerful reflecting telescope of 12 inches diameter, made by Short--
that justly celebrated pioneer of telescope making. It had been erected
in a temporary observatory on the Calton Hill, Edinburgh. These
descriptions of my father's so fired me with the desire to obtain a
sight of the glorious objects in the heavens through a more powerful
instrument than the spy-glass, that I determined to try and make a
reflecting telescope which I hoped might in some degree satisfy my
ardent desires.
I accordingly searched for the requisite practical instruction in the
pages of the Encyclopedia Britannica, and in other books that professed
to give the necessary technical information on the subject. I found,
however, that the information given in books--at least in the books
to which I had access was meagre and unsatisfactory. Nevertheless I set
to work with all earnestness, and began by compounding the requisite
alloy for casting a speculum of 8 inches diameter. This alloy consisted
of 32 parts of copper, 15 parts of grain tin, and 1 part of white arsenic.
These ingredients, when melted together, yielded a compound metal which
possessed a high degree of brilliancy. Having made a wooden pattern for
my intended 8-inch diameter speculum, and moulded it in sand,
I cast this my first reflecting telescope speculum according to the
best book instructions. I allowed my casting to cool in the mould in
the slowest possible manner; for such is the excessive brittleness of
this alloy (though composed of two of the toughest of metals) that in
any sudden change of temperature, or want of due delicacy in handling
it, it is very apt to give way, and a fracture more or less serious is
sure to result. Even glass, brittle though it be, is strong in
comparison with speculum metal of the above proportions, though,
as I have said, it yields the most brilliant composition.
Notwithstanding the observance of all due care in respect of the
annealing of the casting by slow cooling, and the utmost care and
delicate handling of it in the process of grinding the surface into the
requisite curve and smoothness suitable to receive the final polish,--
I was on more than one occasion inexpressibly mortified by the sudden
disruption and breaking up of my speculum. Thus many hours of anxious
care and labour proved of no avail. I had to begin again and proceed
da capo. I observed, however, that the surplus alloy that was left in
the crucible, after I had cast my speculum, when again melted and
poured out into a metal ingot mould, yielded a cake that, brittle
though it might be, was yet strong in comparison with that of the
speculum cast in the sand mould; and that it was also, judging from the
fragments chipped from it, possessed of even a higher degree of
brilliancy.
The happy thought occurred to me of substituting an open metal mould
for the closed sand one. I soon had the metal mould ready for casting.
It consisted of a base plate of cast iron, on the surface of which I
placed a ring or hoop of iron turned to fully the diameter of the
intended speculum, so as to anticipate the contraction of the alloy.
The result of the very first trial of this simple metal mould was most
satisfactory. It yielded me a very perfect casting: and it passed
successively through the ordeal of the first rough grinding, and
eventually through the processes of polishing, until in the end it
exhibited a brilliancy that far exceeded that of the sand mould
castings.
The only remaining difficulty that I had to surmount was the risk of
defects in the surface of the speculum. These sometimes result from the
first splash of the melted metal as it is poured into the ring mould.
The globules sometimes got oxidised before they became incorporated
with the main body of the inflowing molten alloy: and dingy spots in
the otherwise brilliant alloy were thus produced. I soon mastered this,
the only remaining source of defect, by a very simple arrangement.
In place of pouring the melted alloy direct into the ring mould, I
attached to the side of it what I termed a "pouring pocket;"
which communicated with an opening at the lower edge of the ring,
and by a self-acting arrangement by which the mould plate was slightly
tilted up, the influx of the molten alloy advanced in one unbroken
tide. As soon as the entire surface of the mould plate was covered by
the alloy, its weight overcame that of my up-tilting counterpoise,
and allowed the entire apparatus to resume its exact level. The
resulting speculum was, by these simple arrangements, absolutely
perfect in soundness. It was a perfect casting, in all respects worthy
of the care and labour which I invested in its future grinding and
polishing, and enabled it to perform its glorious duties as the grand
essential part of a noble reflecting telescope!
[Image]
A. Chill plate of cast iron turned to the curve of the speculum B.
Turned hoop of wrought iron with opening at O. C. Pouring pocket. D.
Counterpoise, By which the chill plate is tilted up The largest figure
in the engraving is the annealing tub of cast iron filled with sawdust,
where the speculum is placed to cool as slowly as possible.
The rationale of the strength of specula cast in this metal mould
system, as compared with the treacherous brittleness of those cast in
sand moulds, arises simply from the consolidation of the molten metal
pool taking place first at the lower surface, next the metal base of
the mould--the yet fluid alloy above satisfying the contractile
requirements of that immediately beneath it; and so on in succession,
until the last to consolidate is the top or upper stratum.
Thus all risk of contractile tension, which is so dangerously eminent
and inherent in the case of sand-mould castings, made of so exceedingly
brittle an alloy as that of speculum metal, is entirely avoided.
By the employment of these simple and effective improvements in the art
of casting the specula for reflecting telescopes, and also by the
contrivance and employment of mechanical means for grinding and
polishing them, I at length completed my first 8-inch diameter
speculum, and mounted it according to the Newtonian plan. I was most
amply rewarded for all the anxious labour I had gone through in
preparing it, by the glorious views it yielded me of the wonderful
objects in the heavens at night. My enjoyment was in no small degree
enhanced by the pleasure it gave to my father, and to many intimate
friends. Amongst these was Sir David Brewster, who took a most lively
and special interest in all my labours on this subject.
In later years I resumed my telescope making enjoyments, as a
delightful and congenial relaxation from the ordinary run of my
business occupations. I constructed several reflecting telescopes,
of sizes from 10-inch to 20-inch diameter specula. I had also the
pleasure of assisting other astronomical friends, by casting and
grinding specula for them. Among these I may mention my late dear
friend William Lassell, and my excellent friend Warren de la Rue,
both of whom have indelibly recorded their names in the annals of
astronomical science. I know of no subject connected with the pursuit
of science which so abounds with exciting and delightful interest as
that of constructing reflecting telescopes. It brings into play every
principle of constructive art, with the inexpressibly glorious reward
of a more intimate acquaintance with the sublime wonders of the
heavens, I communicated in full detail all my improvements in the art
of casting, grinding, and polishing the specula of reflecting
telescopes, to the Literary and Philosophical Society of Manchester,
illustrating my paper with many drawings. But as my paper was of
considerable length, and as the illustrations would prove costly to
engrave, it was not published in the Society's Transactions. They are
still, however, kept in the library for reference by those who take a
special interest in the subject.
1829. A Mode of transmitting Rotary Motion by means of a Flexible
Shaft, formed of a Coiled Spiral Wire or Rod of Steel.
While assisting Mr. Maudslay in the execution of a special piece of
machinery, in which it became necessary to have some holes drilled in
rather inaccessible portions of the work in hand, and where the
employment of the ordinary drill was impossible, it occurred to me that
a flexible shaft, formed of a closely coiled spiral of steel wire,
might enable us to transmit the requisite rotary motion to a drill
attached to the end of this spiral shaft. Mr. Maudslay was much pleased
with the notion, and I speedily put it in action by a close coiled
spiral wire of about two feet in length.
This was found to transmit the requisite rotary motion to the drill at
the end of the spiral with perfect and faithful efficiency.
The difficulty was got over, to Mr. Maudslay's great satisfaction.
So far as I am aware, such a mode of transmitting rotary motion was new
and original. The device was useful, and proved of essential service in
other important applications. By a suitably close coiled spiral steel
wire I have conveyed rotary motion quite round an obstacle, such as is
indicated in the annexed figure.
[Image]
It has acted with perfect faithfulness from the winch handle at A to
the drill at B. Any ingenious mechanic will be able to appreciate the
value of such a flexible shaft in many applications. Four years ago I
saw the same arrangement in action at a dentist's operating-room, when
a drill was worked in the mouth of a patient to enable a decayed tooth
to be stopped. It was said to be the last thing out in "Yankee notions."
It was merely a replica of my flexible drill of 1829.
1829. A Mode of cutting Square or Hexgonal Collares Nuts or Bolt-Heads
by means of a Revolving File or Cutter.
This method is refrered to, and drawings given, in the text,
pp. 141, 142.
1829. A Investigation into the Origin and Mode of writing the Cuneiform
Character
This will be found described in the next and final chapter
1836. A Machine for cutting the Key-Grooves in Metal Wheels and Belt
Pulleys, of ANY Diameter.
The fastening of wheels and belt pulleys to shafts, so as to enable
them to transmit rotary motion, is one of the most frequently-recurring
processes in the construction of machinery. This is best effected by
driving a slightly tapered iron or steel wedge, or "key" as it is
technically termed, into a corresponding recess, or flat part of the
shaft, so that the wheel and shaft thus become in effect one solid
structure.
The old mode of cutting such key-grooves in the eyes of wheels was
accomplished by the laborious and costly process of chipping and
filing. Maudslay's mortising machine, which he contrived for the Block
machinery, although intended originally to operate upon wood, contained
all the essential principles and details required for acting on metals.
Mr. Richard Roberts, by some excellent modifications, enabled it to
mortise or cut out the key-grooves in metal wheels, and this method
soon came into general use. This machine consisted of a vertical slide
bar, to the lower end of which was attached the steel mortising tool,
which received its requisite up and down motion from an adjustable
crank, through a suitable arrangement of the gearing. The wheel to be
operated upon was fixed to a slide-table, and gradually advanced,
so as to cause the mortising tool to take successive cuts through the
depth of the eye of the wheel, until the mortise or key-groove had
attained its required depth.
The only drawback to this admirable machine was that its service was
limited in respect to admitting wheels whose half diameter did not
exceed the distance from the back of the jaw of the machine to the face
of the mortise tool; so that to give to this machine the requisite
rigidity and strength to resist the strain on the jaw, due to the
mortising of the key-grooves, in wheels of say 6 feet diameter,
a more massive and cumbrous frame work was required, which was most
costly in space as well as in money.
In order to obviate this inconvenience, I designed an arrangement of a
key-groove mortising machine. It was capable of operating upon wheels
of any diameter, having no limit to it capacity in that respect.
It was, at the same time, possessed in respect of the principle on
which it was arranged, of the power of taking a much deeper cut,
there being an entire absence of any source of springing or elasticity
in its structure. This not only enabled the machine to perform its work
with more rapidity, but also with more precision. Besides, it occupied
much less space in the workshop, and did not cost above one-third of
the machines formerly in use. It gave the highest satisfaction to those
who availed themselves of its effective Services.
[Image]
A comparison of Fig. 1--which represents the general arrangement of
the machine in use previous to the introduction of mine--with that of
Fig. 2, may serve to convey some idea of their relative sizes. Fig. 1
shows a limit to the admission of wheels exceeding 6 feet diameter,
Fig. 2 shows an unlimited capability in that respect.
1836. An Instrument for finding and marking the Centres of Cylindrical
Rods or Bolts about to be turned on the Lathe.
One of the most numerous details in the structure of all classes of
machines is the bolts which serve to hold the various parts together.
As it is most important that each bolt fits perfectly the hole it
belongs to, it is requisite that each bolt should, by the process of
turning, be made perfectly cylindrical. In preparing such bolts,
as they come from the forge, in order to undergo the process of
turning, they have to be "centred;" that is, each end has to receive a
hollow conical indent, which must agree with the axis of the bolt.
To find this in the usual mode, by trial and frequent error, is a most
tedious process, and consumes much valuable time of the workman as well
as his lathe.
[Image]
In order to obviate the necessity for this costly process, I devised
the simple instrument, a drawing of which is annexed. The use of this
enabled any boy to find and mark with absolute exactness and rapidity
the centres of each end of bolts, or suchlike objects. All that was
required was to place the body of the bolt in the V-shaped supports,
and to gently cause it to revolve, pressing it longitudinally against
the steel-pointed marker, which scratched a neat small circle in the
true centre or axis of the bolt. This small circle had its centre
easily marked by the indent of a punch, and the work was thus ready for
the lathe. This humble but really important process was accomplished
with ease, rapidity, and great economy.
1836. Improvement in Steam-Engine Pistons, and in Water and Air-Pump
Buckets, so as to lessen Friction and dispense with Packing.
The desire to make the pistons of steam-engines and air-pump buckets of
condensing engines perfectly steam and water tight has led to the
contrivance of many complex and costly constructions for the purpose of
packing them. When we take a commonsense view of the subject, we find
that in most cases the loss of power resulting from the extra friction
neutralises the expected saving. This is especially the case with the
air-pump bucket of a condensing steam-engine, as it is in reality much
more a water than an air pump. But when it is constructed with a deep
well-fitted bucket, entirely without packing, the loss sustained by
such an insignificant amount of leakage as may occur from the want of
packing is more than compensated by the saving of power resulting from
the total absence of friction.
The first condensing steam-engine to which I applied an air-pump
bucket, entirely without packing, was the forty horsepower engine,
which I constructed for the Bridgewater Foundry. It answered its
purpose so well that, after twenty years' constant working,
the air-pump cover was taken off, out of curiosity, to examine the
bucket, when it was found in perfect order. This system, in which I
dispensed with the packing for air-pump buckets of condensing
steam-engines, I have also applied to the pistons of the steam
cylinders, especially those of high-pressure engines of the smaller
vertical construction, the stroke of which is generally short and
rapid. Provided the cylinder is bored true, and the piston is carefully
fitted, and of a considerable depth in proportion to its diameter,
such pistons will be found to perform perfectly all their functions,
and with a total absence of friction as a direct result of the absence
of packing. By the aid of our improved machine tools, cylinders can now
be bored with such perfect accuracy, and the pistons be fitted to them
with such absolute exactness, that the small quantity of water which
the steam always deposits on the upper side of the piston, not only
serves as a frictionless packing, but also serves as a lubricant of the
most appropriate kind. I have applied the same kind of piston to
ordinary water-pumps, with similar excellent results. In most cases of
right packed pistons we spend a shilling--to save sixpence--
a not unfrequent result of "so-called" refined improvements.
1836. An instantaneous Mode of producing graceful Curves, suitable for
designing Vases and other graceful objects in Pottery and Glass.
The mode referred to consists in giving a rapid "switch" motion to a
pencil upon a piece of paper, or a cardboard, or a smooth metal plate;
and then cutting out the curve so produced, and employing it as a
pattern or "template," to enable copies to be traced from it.
When placed at equal distances, and at equal angles on each side of a
central line, so as to secure perfect symmetry of form according to the
nature of the required design, the beauty of these "instantaneous"
curves, as I term them, arises from the entire absence of any sudden
variation in their course. This is due to the momentum of the hand when
"switching" the pencil at a high velocity over the paper.
By such simple means was the beautiful curve produced, which is given
on the following page. It was produced "in a twinkling," if I may use
the term to express the rapidity with which it was "switched."
The chief source of the gracefulness of these curves consists in the
almost imperceptible manner in which they pass in their course from one
degree of curvature into another. I have had the pleasure of showing
this simple mode of producing graceful curves to several potters,
who have turned the idea to good account. The illustrative figures on
the next page have all been drawn from "templates" whose curves were
"switched" in the manner of Fig. A.
[Image]
1836. A Machine for planing the smaller or detail parts of Machinery,
whether Flat or Cylindrical.
Although the introduction of the planing machine into the workshops of
mechanical engineers yielded results of the highest importance in
perfecting and economising the production of machinery generally, yet,
as the employment of these valuable machine tools was chiefly intended
to assist in the execution of the larger parts of machine manufacture,
a very considerable proportion of the detail parts still continued to
be executed by hand labour, in which the chisel and the file were the
chief instruments employed. The results were consequently very
unsatisfactory, both as regards inaccuracy and costliness.
[image]
With the desire of rendering the valuable services of the Planing
Machine applicable to the smallest detail parts of machine manufacture,
I designed a simple and compact modification of it, such as should
enable any attentive lad to execute all the detail parts of the
machines in so unerring and perfect a manner as not only to rival the
hand work of the most skilful mechanic, but also at such a reduced cost
as to place the most active hand workman far into the background.
The contrivance I refer to is usually known as "Nasmyth's Steam Arm."
None but those who have had ample opportunities of watching the process
of executing the detail parts of machines, can form a correct idea of
the great amount of time that is practically wasted and unproductive,
even when highly-skilled and careful workmen are employed. They have so
frequently to stop working, in order to examine the work in hand,
to use the straight edge, the square, or the calipers, to ascertain
whether they are "working correctly." During that interval, the work is
making no progress: and the loss of time on this account is not less
than one-sixth of the working hours, and sometimes much more;
though all this lost time is fully paid for in wages.
[Image] Apparatus for enabling the machine to execute segmented work