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 n.o.ble 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 a.s.sumptions 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 a.s.sent. 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 circ.u.mstances 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 s.p.a.ce 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 a.s.sistant 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 a.s.sistants 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 circ.u.mstances, 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, Middles.e.x, 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, Middles.e.x, 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 gla.s.s, 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 gla.s.s, 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] Gla.s.s globe cracked by internal pressure, in ill.u.s.tration 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 gla.s.s globe filled with water and hermetically sealed. The water was then slightly expanded, on which the gla.s.s 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 ill.u.s.tration of this. .h.i.therto 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 pa.s.sengers (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 a.s.sociation 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 Mitch.e.l.l, 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 const.i.tuents 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 circ.u.mstance 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 La.s.sell.