1866 JOURNAL OF THE
PHOTOGRAPHIC SOCIETY (London)
VOL. XI (1866-1867)
Ver: Mar. 7, 2007
TRANSCRIPTION CONVENTIONS:
--Italics have been retained from publications, which uses them for both titles as well as emphasis. To more easily locate image titles, I have continued this italicization when titles have been rendered in all capitols or put in quotes, however italics have NOT been used when the general subject of an image is mentioned.
--Photographer’s (or potential photographer’s) names have been bolded – see also below under “Names”
--Brackets [ ] are used to indicate supplied comments by the transcriber; parenthesis
( ) are used in the original sources. If the original source has used brackets, they have been transcribed as parenthesis to avoid confusion.
--Spelling and typos: Nineteenth-century spellings occasionally differs from currently accepted norms. In addition, British spellings also differ from American usage. Common examples are: “colour” vs. “color”; “centre” vs. “center” and the use of “s” for “z” as in “recognise” vs. “recognize. While great care has been exercised in transcribing the 19th-century journals exactly as printed, “spell check” automatically corrects many of these differences. An attempt has been made to recorrect these automatic changes, but no doubt some have slipped through. As for typographical errors, these have been checked although no doubt some have managed to slip through the editorial process. For matters of consequence, I will be happy to recheck the original sources if need be for specific references.
-- Technical articles: For the most part, articles discussing technical aspects of photography, products, etc. were not transcribed unless they are part of a larger article covering photographs. When technical descriptions are too lengthy to include, that has been noted. Exceptions have been made as the transcriber saw fit.
--Meetings of Societies: Names of officers, members attending or referenced, dates and locations of meetings have been given. The first and/or earliest meetings recorded have been transcribed in full. Beyond those early years, only if the reports are very short or discuss photographs, have the articles been copied in full; if administrative or technical in nature. Although not always possible due to time constraints on borrowed materials, when possible, I have included at least the dates of society meetings and any photographer’s names listed.
-- Related, contemporary journals: e.g., The Art-Journal, cover both photographer as well as painting, drawing, sculpture, etc.. As they frequently refer to the production of both the photographer and the painter as “pictures” it is not always possible to tell when photography is indicated. If there is doubt, these articles have been included and the names bolded, but the individuals may, in fact, not be photographers.
NAMES:
--All photographer’s names have been bolded for easy location. EXCEPTIONS: While it is likely that people working with photographic equipment and techniques are also photographers some discretion has been used and not all such names have been bolded. Names of honorary members of a photographic society are assumed to be photographers and thus bolded, when in fact, that may not be the case. Names mentioned in connection with meetings of non-photographic societies have not been bolded unless there is a known or suspected photographic association. A computer word search, however, will still enable the researcher to locate any references to specific names.
--Names: Given abbreviations for titles such as “M” for “Monsieur”, etc., it is not always possible to tell if an individual’s first name or title is being abbreviated. Thus, especially with non-English photographers, too much credence should not be put into an initial that could also serve as an abbreviated title.
--It is not always possible in lists of photographers to know when two separate photographers are partners or not, e.g., in a list, “Smith and Jones” sometimes alludes to two separate photographers and sometimes to one photographic company. Both names will be highlighted and indexed but a partnership may be wrongly assumed. Any information to the contrary would be appreciated.
NUMBERS:
--Numbers referenced in the various journals can refer to either the photographer’s image number, or an entry number in an exhibition catalog. When the number is obviously is obviously that of the photographer, it is included in the index under the photographer’s name, whereas exhibition numbers are not.
1866: JPS, June 16, vol. XI, #170, p. 51-52:
Photographic Society of London. Ordinary General Meeting. Tuesday, June 12, 1866.
The Lord Chief Baron, F.R.S., in the Chair.
The Secretary read the Minutes of the last meeting, which were confirmed.
The following gentlemen were elected Members of the Society:--
Lieut.-Gen. Williams, Cheltenham.
Mr. Martin, Regent Street
Mr. Benjamin Green.
The President—Gentleman, I was at the bar a great many years, and I never had so bad a case as I have to state to-night, and I feel very much ashamed of it. I believe statements went forth to the Members of the Photographic Society that certain medal were to be distributed this evening. I( am sorry to say there is considerable difficulty in fulfilling the promises held out to this Society. Medals were to be distributed, but there are two difficulties: there are no medals to distribute; and perhaps you would say that of itself would be sufficient, without going any further; but there is also considerable difficulty in reference to the presence of persons to receive them. I can not say there are none here to whom they would be given, but it would be desirable that the more conspicuous persons intended to be done honour to should be present, and they are not; apologies from at lest three or four, who cannot be here, have been received. Whether that is owing to the great improvement of the weather, I do not know; but here they are not. How can I distribute medals without medals to distribute, and when many of the persons who are to receive them are not here? […continues in the line…] I do expect—and everything that occurs induces me to expect it more confidently—that the labours of photographers, who contribute largely to the pleasure of the public in a great variety of ways—I say I do expect that their labours will advance the science so as to promote a study of the elements, if I may so say, of which the art of photography is composed, and increase our acquaintance with the properties of light, and the circumstances under which the phenomena connected with light and heat, and electricity and magnetism, and other phenomena of nature which are still subjects of considerable doubt and difficulty are produced, so as to extend largely the bounds of human knowledge.
The more general opinion, as you are aware, is that there is a remarkably fine æther which proceeds from sun to sun and extends probably through the whole of space. When we learn that there are stars that we now see by vibrations of light which proceeded from the original source ten thousand years ago, and when we know that light goes from the earth to the moon in one second of time, we can appreciate what extreme distance would be required to occupy ten thousand years in the traversing of a vibration such as light is; and when we examine and consider all that we know about what is called the polarization of light, one of the most remarkable phenomena that the optical instrument discloses to us, it appears to me that we are really on the threshold of making considerable discoveries. Probably I am not wrong in stating that within the last hundred years there has been more added to the physiological knowledge of man, of the planet which he inhabits, and the materials which surround him, in the proportion of at least one hundred to one of what was known before—and if in that time, by the exertions of chemists, of astronomers, of geologists, and I will say at last of those who have studied light, and amongst others photographers, what are we to expect in the course of the next fifty or hundred years? The subject is one which I own I have been deeply impressed with.
For a great many years I have been not merely a lawyer, not merely even a student, a classic, a mathematician, but I have always considered the study of the works of nature the great matter which ought to interest everybody who desires to advance the power of man, and to conquer and penetrate into all the secrets of creation. I own I do expect, and when you first honoured me by putting me in this chair I said I did expect, great assistance from the photographic labours of those who practically and also scientifically undertook the works which now are ordinarily called photographic. This is not the first time I have mentioned the success of Mr. De la Rue in reference to the study of astronomy. He has solved a problem which certainly puzzled everybody before him, and he has revealed to the world that which can be seen by the eye of photography alone. If you look with any ordinary instrument into the sun you are—to borrow, I think, the expression of some port—“blasted by excess of light.” You cannot see; there is too much light, you are overpowered; but the eye of photography can reject what is superfluous and employ that which is useful; and Mr. De la Rue discovered by its means the figure of the sun and the projections from it in a manner the most satisfactory and astonishing. You are overpowered by the extraordinary character of the discovery, at the same time that you find it is free from any possible objection. I have been in hopes (and I should have made a great effort to be present if the hope had been realized)—indeed I had from Mr. De la Rue personally a promise that he would come here and deliver a lecture some evening upon that particular part of his discovery. I am sorry to say, from various causes, he has been unable to come; but I hope we shall have the opportunity of listening to him in the course of next session. I mention this because it is one of the instances in which photography has done that which nothing else could do, and which never had been done before. … [meeting continues]
1866: JPS, June 16, vol. XI, #170, p. 67-68:
Soirée of the Photographic Society at King’s College, June 7th.
The Soirée has been admitted to have been perfectly successful in every respect. The large number of about 600 visitors included many of the distinguished men of the various learned Societies. In the early part of the evening the guests were received by the Vice-Presidents,--the Lord Chief Baron, accompanied by Baron Bramwell, arriving later, in their judicial wigs and robes. For reasons already assigned, it had been determined that no separate exhibition should be held this year, it was therefore wished that the soirée should, as far as possible, partake of the nature of an exhibition, and that those who had any novelties to bring before the public might thus be enabled to do so so, [sic] and afford, at the same time, gratification to those who visited King’s College. The Secretary addressed upwards of 200 circulars to the members of the Society and their friends, asking for cooperation, to render the Soirée attractive. To that request the following exhibitors responded by contributions. Others may have done so as well; but any omissions in the record must depend on a reply not having been forwarded to the Secretary.
The Rev. W. Ellis, Hoddesdon.
An extensive series of views in Madagascar. These pictures were taken during Mr. Ellis’s late residence in Madagascar, an account of which, no doubt, will be published; and if illustrated by aid of these truthful photographs, its interest will be greatly increased. Ambohimanga (the chief of the royal and sacred cities, one which no European is allowed to enter),--Antanarivo (the chief city of Nayadon), and Ambohipotsy (the spot where the first Christian martyrs were put to death) we may mention as exiciting especial attention.
Mr. Jabez Hughes, Ryge,
A series of views of the iron-clad fleet, together with excellent instantaneous photographs.
Lieut.-Col. A.N. Scott, Royal Artillery.
A series of thirty stereoscopic views of scenes in India, illustrating manners and customs at Madras.
The Casket Portrait Company.
A collection of their works, exhibiting a solid binocular relief to the naked eye (Swan’s patent).
Mr. H. Claudet.
A series of ten extra full-size portraits 12 x 10 ½. These pictures are taken direct without enlargement, and are the effect of photography alone, without the after-touching of the artist. They are excellent specimens of the class of work which, in Mr. Claudet’s hands, has been so much appreciated by the public.
Mr. Charles Heisch.
Four attractive frames of photographs, one, of the Medical Staff of the Middlesex Hospital well arranged in a group, being of much interest, both for the excellence of the majority of the portraits and as showing how satisfactory such records may be made when taken by able persons.
Messrs. Lock Whitfield.
Three frames of photographic pictures, having all the elaborate treatment for which their works are so justly celebrated.
Mr. R. L. Allan.
Photographs and transparencies done by “Allan’s process,” one which, we trust, the author will allow us to give practical instructions for the working of in a future number of this Journal.
The Stereoscopic Company, Regent Street.
A portrait of Chang, the Chinese giant, life-size, together with some excellent subjects for small pictures.
Mr. D. H. Macfarlane, London.
A series of ten large views of domestic and other scenery.
Mr. E. B. Buxton, Dunesbury Hall.
Photographs of scenes in India.
*** To both Mr. Macfarlane and Mr. Buxton the Silver Medals of the Society were respectively awarded at the last exhibition, for the great excellence of their pictures.
Mr. Fox, Brighton.
An interesting group of photographs, showing trees from nature, with and without leaves, the same trees being delineated in both states.
Mr. How, Foster Lane.
Three frames of photographs executed by Dr. Maddox; also other microscopic photographs. The Society awarded a Silver Medal to Dr. Maddox for the excellence of his pictures.
Mrs. Pointer, Brighton.
An admirable copy of an oil painting executed by her husband.
Mr. H. C. Heath, Regent Street.
Very attractive and exceedingly well executed enlargements, plain and coloured, from Carte-de-visite pictures.
Mr. Ross, Featherstone Buildings.
An extensive series of views calculated to exhibit the excellence of working of the various forms of lenses which have been used in their production.
Messrs. Marion, Son & Co., Soho Square.
Six framed and coloured photographs of Turner’s pictures, taken from the paintings in the National Gallery by Mr. C., Thurston Thompson; also some interesting volumes of photographs.
Mr. Mayal, Regent Street.
A series of portraits of Tennyson the poet, Earl Russell, Mr. Peabody, the artist’s own portrait, and other excellent enlargements, taken by aid of the solar camera.
Mr. Dallmeyer, Bloomsbury.
Pictures lately taken by Mr. H. P. Robinson; some of these were exhibited at the May Meeting of the Society, but others of a more recent date. They have a beauty and reality which we have never before seen so wonderfully represented by photography.
Mr. Frank M. Good, Minories.
Thirteen frames of landscapes and antiquities, most carefully and artistically treated.
Mr. Ritchie.
Three various frames.
Mr. Snoswell, Notting Hill, and Mr. Field, the Mint.
Views in the Tower of London.
Mr. W. Warwick King, Queen Street.
Five various frames of views and antiquities.
Mr. Samuel Fry, Surbiton.
Enlargements and other pictures, well executed.
Mr. George Cox, Southwick Street.
Illustrations of Hop-gathering at Barming Heath and other localities near Maidstone, forming a very interesting series. These pictures were all taken by the Tannin process, which has been more successful in his hands than in the majority of operators’; they exhibit, however, the dullness of the process compared to the Fothergill or Collodio-albumen.
Mr. Alfred T. heath, Camden Street.
Some beautiful portraits.
Mr. Edward Dunmore, Malden Road.
A view of St. Paul’s, one of the best yet done; rustic views, &c.
Messrs. Moire & Haig, London.
Some of the best transparencies which we have ever seen, plain and coloured; being mounted in an elegant manner, they form very attractive objects of art for convenient display.
Mr. Bedford, Camden Road.
Twenty-five frames of pictures, some of the best of Mr. Bedford’s works, so justly admired by every one.
Mr. English, St. James’s Square, Notting Hill.
The well-known series of Alpine and other views. During the evening our attention was frequently called to the excellence of the pictures by those who beheld them.
Mr. Bambridge.
The portraits of the dogs in the Royal Kennel at Windsor, taken by command of her Majesty, together with cattle bred at the Royal Farm. A selection of these pictures, we feel confident, would be much appreciated by the public, if Mr. Bambridge would publish them. They are also remarkable for the care which ahs been used in printing them.
Mrs. Cameron.
A series of pictures, most of which were nearly life-sized heads, taken direct, without enlargement. They were much admired for the artistic feeling they exhibited.
Mr. J. J. Cole, Victoria Terrace.
] A series of pictures from Mr. Moens, the late captive of the brigands.
Mr. Solomon, Red Lion Square.
Exhibited the perfect action of the light of magnesium burnt by aid of his lamp. The exhibitor added much to the attractions of the evening.
1866: JPS, July 16, vol. XI, #171, p. 77-84:
De La Rue and Celestial Photography† (†From the Quarterly Journal of Science)
It is about twenty-seven years since we were told of a remarkable discovery, made by a Frenchman, of a process by which external objects were made to delineate themselves on prepared metal plates, placed in a camera obscura, with a perfection of detail and a delicacy of delineation which had never been approached by the human hand. The pictures so produced by Daguerre were seen and admired. The world of science, once awakened to the fact that the sun’s rays could be made to copy on prepared tablets the objects which they illuminated, went busily to work, investigating the curious phenomena involved in the art of photography. It must not be forgotten that Wedgwood, assisted by Davy, produced unstable photographic pictures in 1803*
(*Carbonate of ammonia is well known to have a variable composition,
commonly supposed to be a sesquicarbonate with water,--2 NH4 O, 3CO2 + 3Aq;
but when sublimed, the first and last product s are never identical, so that the
commercial salt will present variable degrees of solubility; these will, however,
lie between the limits of 30 parts in 100 of water at 60° F. (Berzelius), and 33
parts (Ure). Exposed to air, it becomes changed to bicarbonate, and falls to a dry
white powder. It costs eight pence per pound.)
Mr. H. Fox Talbot, soon after the announcement of Daguerre’s discovery, produced his “Photogenic” drawings, speedily followed by his beautiful “calotype” pictures. Sir John Herschel investigated, with much industry and skill, the chemical changes produced upon organic and inorganic substances by solar agencies;’ and Mr. Robert Hunt published, in rapid succession, his discoveries of the developing-power of the protosulphate of iron, of the influence of the chemical rays in accelerating the germination of seeds, his “chromatype” and other processes for producing photographic pictures. Beyond this, at the second Meeting of the British Association, at York, in 1844, this photographer showed that the chemical changes produced by the sun’s rays were not due to their luminous power, but were the consequence of dark radiations, for which principle or power he proposed the name of Actinism—a term which has been generally adopted.
These researches appeared to confirm the results obtained and the hypotheses propounded by M. Berard in 18912, which were reported upon by Berthollet, Chaptel, and Biot.†
(† “To show clearly the great disproportion which exists in this respect between
the energies of different rays, M. Berard concentrated by means of a lens, all that
part of the spectrum which extends from the green to the extreme violet, and he
concentrated, by means of another lens, all that portion which extends from the
green to the extremity of the red. This last pencil formed a point so brilliant that
the eyes were scarcely able to endure it, yet the muriate of silver remained
exposed more than two hours to this brilliant point of light without undergoing
any sensible alteration. On the other hand, when exposed to the other pencil,
which was much less bright and less hot, it was blackened in less than six
minutes.”—Annales de Chimie, vol. lxxxv, p. 309. Se also “Report on the
Chemical Action of Solar Radiations,” Report of British Association for 1850, p.
140)
A few years passed away, Professor Schönbein discovered gun-cotton, and at the Meeting of the British Association at Southampton, in 1846, he introduced it as an important improvement upon gunpowder. As a destructive agent, guncotton has been slow in making its way as an agent for projecting cannon-balls or for rending rocks; but dissolve ed in ether, it forms that collodion which Mr. Archer (in 1851) taught us how to use in multiplying images of the beautiful; and the process to which it has given its name is now universally adopted, to the almost entire exclusion of every other kind of photographic manipulation.
At a very early period (1838-1840) it was seen that the changes produced on the salts of silver by the sun’s rays might be used to render meteorological and other instruments self-registering. In 1858, Mr. T. B. Jordan, then Secretary of the Royal Cornwall Polytechnic Society, devised and used photographic methods for registering barometers, thermometers, and magnetometers.* (*On a New Method of Registering the Indications of Meteorological Instruments. By T. B. Jordan, Sixth Report of Royal Cornwall Polytechnic Society, 1838) These methods, modified by Mr. Brooks and Mr. Ronalds, were subsequently introduced into the observatories at Kew and at Greenwich, where, at the latter especially, under the direction of Professor Airy, a beam of artificial light now registers through each day and night every movement of those steel bars which tell us of the variations in the earth’s magnetic intensity, and of the occurrence of the strange phenomena known as “Magnetic Storms,” now proved, by the investigations of General Sabine, to be intimately connected with those solar spots which are being explored (if the term is admissible) by Celestial Photography. While photography was making progress as an art, it was employed in a few hands as an aid in scientific investigation. Sir John Herschel especially used chemical compounds sensitive to solar influences to determine the relative values of the solar radiations proceeding from different parts of the sun’s disk; and this led to the determination of the fact, at the same time by two distinct observers,† (†Philosophical Magazine, vol. xvi. 3rd series, contains an abstract of the memoir read before the Royal Society by Sir John Herschel; and there is also a paper in the same monthly part of this magazine, by Robert Hunt, “On Experiments and observations on Light which ahs permeated coloured Media, and on the Chemical Action of the Solar Spectrum,”—in both of which this fact was for the first time stated.) that the chemical action produced by the rays coming from the edge of the sun were less active than those proceeding from its central regions. This fact has been, strangely enough, recently put forward as a discovery by Professor Roscoe,‡ (‡On the Measurement of the Chemical Brightness of various Portions of the Sun’s Disk. By Henry Enfield Roscoe, B.A. F.R.S. Received June 12, 1863.) without the mention of any previous observer, excepting Secchi, which observations had reference to the calorific, and not to the chemical radiations. It is true that Professor Roscoe has made a series of excellent experimental observations, and that he has proved “that the intensity of the chemically active rays at the centre is from three to five times as great as that at the edge of the disk;” but in doing this he has only confirmed the results already published.* (*See “On the Present State of our Knowledge of the Chemical Action of the Solar Radiations,” by Robert Hunt: Report of the British Association, 1850, p. 137) For example, in 1840 Sir John Herschel, in the Philosophical Transactions, part 1, p. 43, distinctly stated that he had detected “a real difference between the chemical agencies of those rays which issue from the central portion of the sun’s disk, and those which, emanating from its borders, have undergone the absorptive action of a much greater depth of its atmosphere; and yet I confess myself somewhat at a loss what other cause to assign for it. It must suffice, however to have thrown out the hint, remarking only that I have other, and, I am disposed to think, decisive evidence of the existence of an absorptive solar atmosphere extending beyond the luminous one. The breadth of the border, I should observe, is small, not exceeding 0·5”, or one-seventh part of the sun’s radius; and this, from the circumstance of the experiment, must necessarily err in excess.”
Mr. Robert Hunt, in the Philosophical Magazine already quoted, noticed the same phenomenon, and gave the same (as being the most familiar) explanation of it; and subsequently, Mr. Arago, in his ‘Memoirs on Photometry,’ again drew attention to this important fact.
The results which have been obtained since 1840 appear to show, not merely that the chemical radiations generated near the edge of the solar disk are absorbed in passing through a greater depth of the sun’s atmosphere, but that there is an actual interference (using this term in its ordinary acceptation rather than its scientific sense) exerted by the luminous radiations, and that the chemical radiations have their origin in a lower zone than that which produces light-energy. The protected band which is seen to surround the prismatic image of the sun is not due to a lowering merely of chemical (actinic) intensity, as would be the case if it were an instance of loss by the absorption in the solar atmosphere; but there is evidence of a changed condition, such as is shown by the protected bands observed under the yellow and the red rays, where luminous and calorific power attain their maximum influence. On this point we have yet a few more words to say.
Professor Bond, of Cambridge, with Messrs. Whipple and Black of Boston in the United States, were the first to make a photographic picture of any celestial body. This was an image of the moon, obtained upon a Daguerreotype plate, which had been placed in the focus of the refracting telescope of the Harvard Conservatory. In 1851 some of these Daguerreotypes of our satellite were in the American department of the Great Exhibition. In 1852, Mr. Warren De La Rue obtained positive lunar photographs, in from ten to thirty seconds, on a collodion film, by means of an equatorially-mounted reflecting telescope of thirteen-inch aperture and ten-feet focal length. At this time Mr. De La Rue had not applied any mechanical driving motion to his telescope. He was therefore constrained to contrive some other means of following the moon’s apparent motion. This he accomplished by hand in the first instance, by keeping a lunar crater always on the wire of the finder, by means of the ordinary hand-gear of the telescope, but subsequently by means of a sliding frame fixed on the eyepiece-holder, the motion of the slide being adjustable to suit the apparent motion of the moon. As the pictorial image of the moon could be seen through the collodion film, and could be rendered immoveable in relation to the collodion plate by causing one of the craters to remain always in apparent contact with a broad wire placed in the focus of a compound microscope affixed to the back of a little camera-box which held the plate, this was effective.
Excellent results were obtained under the disadvantages of the want of an automatic driving motion, which proved how perfectly the hand may be made to obey the eye. Mr. Warren De La Rue was admirably aided in his earliest experiments by Mr. Thornthwaite, since it was found impossible to work without the assistance of an experienced coadjutor.
In 1853 Professor John Phillips communicated to the Hull Meeting of the British Association the results of his experience in Lunar Photography, and he then exhibited some excellent pictures of our satellite. Mr. Hartnup, of Liverpool, aided by Mr. Crooke and other photographers, took some good pictures of the moon in 1854. Father Secchi, at Rome, Mr. Fry, in Mr. Howell’s observatory at Brighton, and Mr. Huggins, now so well known by his application of spectrum analysis to the stars, nebulæ, and comets, also produced lunar pictures. A great extension of Celestial Photography was promised in 1857 by Professor Bond, who applied the process in measuring the distance and angle of position of double stars, and also in determining their magnitude. He succeeded in obtaining pictures of fixed stars down to the 6th or 7th magnitude; and everything gave promise of a fruitful future, when death put a stop to his labours.
In the same year (1857) Mr. Warren De La Rue was successful in applying a driving motion to his telescope, which answered every purpose desired; and since that time he has unremittingly followed up the subject of Celestial Photography whenever his occupations and the state of the atmosphere permitted it.
The Academy of Sciences of Paris has lately recognized Mr. Dr La Rue’s labours by the high distinction of the Lalande prize of Astronomy. From the address which was delivered on the occasion of its presentation, many of the following notices have been derived. As the facts thus detailed have all been subjected to the most searching examination, they stand beyond suspicion, and furnish the most reliable record which it is possible to give of the progress which has been made in an inquiry involving the sue of the most perfect astronomical instruments, the most delicate physical appliances, and the most sensitive chemical preparations, directed by a zealous and thoughtful mind. It has been by means of an equatorial reflecting telescope of thirteen inches aperture, designed by himself and constructed in his own workshop, that Mr. Warren De La Rue has obtained that degree of perfection in Astronomical Photography which has earned for him the gold medal of the Astronomical Society and the Royal medal of the Royal Society.
His splendid photographic delineations of our satellite, with which the scientific world is familiar, owe their excellence, first, to the perfection to which the optical part of the telescope was brought by machinery of his own contrivance, and, secondly, to the remarkable performance of his clockwork driving-apparatus, which not only works smoothly and equably, but is capable of rapid and easy adjustment to the ever-varying velocity of the moon. Mr. De La Rue’s chemical training has, moreover, enabled him to secure that nice balance of affinities in his photographic preparations which has materially reduced the time required to impress the image on the sensitive tablet, and consequently to diminish the bad effects of disturbance of the image, resulting from the unsteadiness of our atmosphere. By these means, pictures of the moon have been repeatedly taken by him in the focus of his reflecting telescope, so perfect as to bear considerable amplification—for example, to thirty-eight inches in diameter. These images admit of measurement with the microscope, so exact as to furnish excellent data for investigations in relation to a supposed physical libration of the moon. These pictures are also now being used as the foundation of the large map of the moon, six feet in diameter, which is being laid down by the Moon Committee of the British Association, as the basis of the intended zone-observations of the lunar surface, by the cooperative action of certain English astronomers. The beautiful stereoscopic views of the moon, with which all are familiar, have done much, and are capable of doing more, in throwing light on the configuration of the lunar surface. It is especially the stereoscopic combinations of enlarged pictures which are calculated to impart a correct knowledge of the relative height and depressions of the terraces, undulations, dykes, and furrows of our satellite.
In pursuing his favourite subject, Mr. De La Rue has successfully taken pictures of Saturn, Jupiter, and Mars, and of some of the fixed stars. The most valuable, however, of Mr. De La Rue’s contributions to astronomical photography was the designing of the photo-heliograph of the Kew Observatory, and subsequently of the micrometer used for measuring the solar autographs, so as to bring them under the domain of calculation.
Sir John Herschel suggested that it would conduce greatly to a true knowledge of our luminary if a daily photographic record of the sun’s surface were obtained. Acting upon this suggestion, and at the request of the Royal Society, Mr. De La Rue designed the Kew heliograph, which was erected at the Kew Observatory of the British Association in 1858, and has since that time been more or less worked.
In 1860 this heliograph was taken to Spain, at the desire of the Royal Society, and was successfully employed by Mr. De La Rue, at Rivabellosa, in obtaining a series of pictures of the solar eclipse of July 18, before, during, and after total obscuration.
In the Bakerian lecture, read before the Royal Society on the 10th of April, 1862, the methods used in measuring these photographs are fully set forth, and the results discussed at length.* (*Philosophical Transactions for 1862, vol. clii. P. 333.)
From an early period several peculiar phenomena have been observed during eclipses of the sun, especially just before and after total obscuration. In 1733, Rydhenius, pastor of Forshem, states, “When the sun was about to lose his light, and also when he was about to recover it, he emitted rays that undulated like the aurora borealis, and were of a fiery red colour.† († Acta Lit. et Scien. Suec. tom. iv. P. 61.) Delisle has recorded an observation made in 1738 of the moon’s shadow passing upon a wall at the moment of total obscuration—tinged with different colours* (* Mémoires pour server à l’Histoire et au Progrés de l’Astronomie. St. Petersburg, 1738.)—by whom made we are not informed; and in 1842 some French astronomers, according to Arago† († Annuaire, 1846, p. 399.), observed similar phenomena to those just described. In 1836, on the occasion of the annular eclipse of May 15, Mr. Baily noticed a very striking appearance, which he thus describes: “When the cusps of the sun were about 40° asunder, a row of lucid points like a string of bright beads, irregular in size and distance from each other, suddenly formed round that part of the circumference of the moon that was about to enter on the sun’s disk.” The same phenomenon occurred in a reverse order at the dissolution of the annulus. This phenomenon had been observed previously (but never so perfectly described, as it was by Mr. Baily‡) (‡ Memoirs of Astronomical Society, vol. x. p.7.) by Halley in 1715, by Delisle in 1724, by Professor Bayne in 1737, by the Rev. Mr. Irvine in 1748, by Mr. S. Webber in 1791§, (§ Consult ‘History of Physical Astronomy,’ by Robert Grant, F.R.A.S.) and some others. Subsequent to Mr. Baily’s observations no opportunity has been lost by astronomers; and other, and yet more remarkable phenomena have claimed especial attention. By far the most striking, and we may almost say inexplicable, are the red protuberances which appear on the edge of the sun when all the direct radiations are obscured by the body of the moon.
The earliest notice which we have of those red protuberances beyond that of Rydhenius, already spoken of, is to b e found in an account of the total eclipse of 1733, by Vassenius, in the Philosophical Transactions of the Royal Society.║ (║Philosophical Transactions, 1733, p. 135.) Vassenius speaks of them as “some reddish spots which appeared in the lunar atmosphere without the periphery of the moon’s disk.” These red spots appear to have attracted occasional attention; but it was not until the eclipse of 1842 that any degree of close observation was directed to them. Mr. Mauvais, who observed this eclipse at Perpignan, described the phenomenon as observed by him. He says, “I cannot give a more exact idea of their aspect than by comparing them to the peaks of the Alps illuminated by the setting sun, and seen afar off”.¶ (¶ Annuaire, 1846, p.409) M. Mayette, an officer of the French Engineers, compared the protuberances, as seen by him, also from Perpignan, to beautiful sheaves of flames. Each observer who has written on this eclipse has described the phenomenon as seen from the several points of observation along the line of totality. Mr. Baily, who was at Pavia, wrote of the luminous protuberances as having the appearance of mountains of a prodigious elevation, the colour of the peach-blossom nearly representing their aspect.* (*Memoirs of Astronomical Society, vol. xv. P.6.) Mr. Airy was near Turin. He remarks, that “in form they somewhat resembled saw-teeth in the position proper for a circular saw.”† († Ibid. p. 16.)
M. Littrow of Vienna, and M. Otto Struve, have given carefully graphic accounts of these protuberances. They have also been noticed by other astronomers in all parts of the world. Sir John Herschel thus describes them: “Distinct and very conspicuous rose-coloured protuberances were seen to project beyond the dark limb of the moon, likened by some to flames, by others to mountains, but which their enormous magnitude and their faint degree of illumination clearly prove to have been cloudy masses of the most excessive tenuity”‡. (‡Outlines of Astronomy, edit. 1850, p. 235.)
In 1851 Dr. Busch succeeded in obtaining a Daguerreotype of the total eclipse of that year with the Königsberg heliometer. In this Daguerreotype the protuberances were seen, but indifferently defined.
In 1859 Mr. De La Rue commenced making the experiments necessary for securing a favourable photographic result, upon the occurrence of the total eclipse of 1860. The difficulties in the way of this were great. These will be gathered best from Mr. De La Rue’s own words: “I made inquiries of those astronomers who had witnessed the eclipse of 1851 respecting the intensity of the light of the corona and red flames as compared with that of the moon, and the relative brightness of one to the other…. The general impression I formed from the information thus derived was, that the light emitted by the corona and red flames taken together was about equal to that of a full moon, less rather than greater’ but no one recollected precisely the brightness of the prominences as compared with that of the corona.”§ (§ Philosophical Transactions, 1862, vol. clii. P.334.) Numerous experiments were made, and it was rendered evident that the utmost sensibility must b e secured in the collodion plates to leave any hope of photographing those “cloudy masses of the most excessive tenuity.” The result of those preliminary experiments was that “nitrate-of-silver baths, prepared in the ordinary way with crystallized nitrate of silver, were taken, and were used in depicting the several phases of the eclipse, with the exception of those of totality. In taking the latter pictures, the baths used were made with nitrate of silver which had been fused carefully in my own laboratory, and were so extremely sensitive that they would give photographs of the full moon in the focus of my reflector in less than a second of time, while with the usual bath five seconds were barely sufficient to give a picture of similar intensity.”* (*Ibid.) Thirty-four cwt. Of apparatus, made up in thirty packing-cases, were conveyed in the ‘Himalaya,’ landed at the port of Bilboa, and thence conveyed to Rivabellosa, a distance of seventy miles, by the ordinary conveyances of the country. Everything was satisfactorily arranged, and “upwards of forty photographs were taken during the eclipse, and a little before and after it;’ two being taken during the totality, on which are depicted the luminous prominences with a precision as to contour and position impossible of attainment by eye-observations.” Thus was achieved a most important end; and we have secured a record of some peculiar solar energy, or its effects, which will greatly aid us in determining the physical condition of the solar mass, and its enveloping gaseous spheres. For a full and detailed account of the apparatus used, and of the methods adopted, as well as for a graphic description of the eclipse itself, we must refer our readers to the Bakerian Lecture already quoted.
In that paper the methods used in measuring the photographs are also fully set forth, and the results discussed at length. It is there shown, by measurement of the positions of the luminous prominences in the totality of pictures obtained at two epochs, one immediately after the disappearance, and the other just before the reappearance of the sun, that the angular change of position of the luminous prominences with respect to the moon corresponds to the theory of their fixature to the sun:--that the “flames” change only apparently, not really, by the moon’s motion over them--that is, as the moon covers one portion and discloses another—and do not otherwise undergo any alteration; so that when the clock by which the telescope was moved, was adjusted to the sun’s motion, the “red flames” stood still. Moreover, it is therein shown by a comparison of the photographic pictures with the optical observations made by Mr. De La Rue at the same time, that luminous prominences invisible to the human eye are depicted in the photographs; thus pointing out and exemplifying by a new experiment the difference which has been frequently shown to exist between the solar, chemical, and luminous radiations.
A curious question arises from the consideration of the chemical power evidently possessed by these prominences, be they flames or clouds. We never, as we have already stated, under orderinary circumstances, obtained an impressed image of the sun without finding the indications of a protected circle (that is, one which proves a paucity of chemical power) surrounding the photographic disk. Yet when the light of the soalr disk is interrupted by the body of the moon, the radiations proceeding from the edge, or rather, perhasps, from beyond it, have a strong photographic power. What is the cause of this most remarkable difference? The question can only be answered satisfactorily by waiting for the evidence of future experiments. Those prominences become visible to the eye during an eclipse, because the eye is protected by the moon from the intense glare of solar light. They evidently belong to the sun. This was yet further proved by a careful examination of the photographs of the same eclipse obtained by Father Secchi. The luminous prominences, due allowance being made for parallax, were identical in both, thus proving that no change takes place in the form of the prominences for a period much longer than the duration of a total eclipse. It must be borne in mind that the eclipse occurred at an interval of seven minutes between Rivabellosa, where Mr. De La Rue was stationed, and Desierto de las Palmas, where Father Secchi was located.”* (* “Comparison of Mr. De La Rue’s and Father Secchi’s Eclipse Photographs. By W. De La Rue, F.R.S.,” Proceedings of the Royal Society, vol. xiii. P. 442.) Now, why is it that the photographic tablet is impressed by those attenuated images during an eclipse—and even by such of them as do not give light enough to be visible at the period of totality—and that they do not effect the required chemical change upon our sensitive plates when the sun is unobscured? The only reply which we are at present in a position to give is, that the diffused light, when the sun is shining, is sufficiently powerful to overcome the weaker chemical radiations of those solar clouds or flames. If they reply approaches correctness, we have additional evidence confirming the view that the two principles existing in the sun-beam—light or luminous power, and actinism or chemical power—are not modifications of the same energy—to use the accepted term of the day—but rather forces balanced against each other, acting indeed in antagonism. That the luminous rays have the power of entirely subduing the chemical rays ahs been shown by several experiments by Sir John Herschel† († “On the Chemical Action of the Rays of the Solar Spectrum,” Philosophical Transactions, 1840.) and others.
Referring to the “Report on Celestial Photography in England, 1859” we find full confirmation of these views. “Portions of the moon, equally bright optically, are by no means equally bright chemically; hence the light and shade in a photograph do not correspond in all cases with the light and shade in the optical picture. Photography thus frequently renders details visible which escape observation optically, and it therefore holds out a promise of a fertile future in selenological researches; for instance, strata of different composition evidently reflect the chemical rays to a grater or less extent, according to their nature, and may be thus distinguished. The lunar surface very near the dark limb is copied photographically with great difficulty; and it sometimes requires an exposure five or six times as long to bring out completely those portions illuminated by a very oblique ray, as others apparently not brighter but more favourably illuminated. The high ground in the southern hemisphere of the moon is more easily copied than the low ground, usually called seas, which abounds in the northern hemisphere. From these circumstances, I ventured in another place (Monthly Notices of Astronomical Society) to suggest that the moon may have an atmosphere of great density, but of very small extent, and that the so-called seas might be covered with vegetation.”* (*Reports of British Association, 1859, p. 145)
In 1853, Professor John Phillips indeed noticed this difference between the visual and the actinic brightness of portions of the lunar surface.† († Ibid.. 1853, Transactions of Sections, p. 16.)
The application of photography to the planets by Mr. Warren De La Rue and others confirms this fact. For example, the occultation of Jupiter by the moon on November 8th, 1856, afforded an excellent opportunity for comparing the relative brightness of our satellite and that planet. On that occasion Jupiter appeared of a pale greenish tinge, not brighter than the crater Plato, and, according to Mr. De La Rue’s estimate, of about one-third the general brilliancy of the moon; but the actinic power was subsequently found to be equal to fully four-sixths or five-sixths of that of the moon. “Saturn,” says the same observer, “required twelve times as long as Jupiter to produce a photograph of equal intensity, on an occasion specially favourable to making the experiment; yet I obtained a picture of Saturn, together with that of the moon, in fifteen seconds on May the 8th of the present year (1859), just as the planet emerged from behind the moon’s disk. The picture of the planet, although faint, is sufficiently distinct to bear enlarging.”
Jupiter, Mars, and Saturn, together with several of the fixed stars, have been photographed; but the promise afforded by these chemical pictures is not of that high character which belongs to those of our satellite. Studying the large picture of the moon, hanging in the Royal Society’s room, which has been produced by the aid of photography, we cannot but feel that we have a wonderfully minute representation of the lunar surface before us. We see and we can measure the heights of her mountains and the depths of her valleys. Her coasts and cliffs, against which we cannot but think an ocean has at one time beaten its waters, are readily determined. We cannot mistake the craters of eruption, and we are puzzled with such as we must call craters of upheaval, vast swellings, the result of some mighty power which was yet insufficient to burst the stony bubble. Precipices so vast that darkness reigns in the profound depths over which they rise, and glens which appear indeed resigned to all the influences which superstition crowds into such weird glom, are there. Can we not trace glacial moraines? But to what are we to refer the mysterious streaks of light which flow from some of the lunar mountains? We cannot but hope, seeing how much has been done, that we shall have continuous photographic records of the moon’s surface. We may then expect to have a more exact knowledge of that lovely orb which belongs especially to our earth, and which is therefore of no common interest to the inquiring mind.
Upon the occasion of Mr. De La Rue’s visit to Rome, an attempt was made, as a secondary object, by comparing the distances of the moon and sun’s centres with the tabular places, to ascertain whether any correction was necessary to the sun and moon’s tabular diameters; and it was found that the latter were in excess of the observed diameters. The correction assigned to the moon’s radius from two sets of the observations has been recently computed to be 2”·15, which agrees closely with the correction Mr. Airy has found to be necessary from M. Breins’s reductions of forty years’ observations of disappearances and reappearances of stars at the moon’s dark limb during occultations.* (* Monthly Notices of Astronomical Society, vol. xxv. P.264.)
From 1860 to the present time, the observations by the Kew heliograph have been placed by the Council of the Royal Society under Mr. De La Rue’s direction. From February 1862 to February 1863, the instrument was removed to the Observatory at Cranford; but a qualified assistant having been trained for the Kew Observatory during that interval, it has been worked continuously at that establishment from May 1863 until the present time.
The object in view is, of course, to obtain the most perfect record possible of all the physical changes which take place on the sun. “The progress of science,” says Mr. De La Rue,* (*Researches on Solar Physics. By Warren De La Rue, F.R.S., Balfour Stewart, F.R.S., and B. Loewy. (First Series, “On the Nature of Sun Spots.”) ) “has hitherto only shrouded in deeper mystery than ever the origin of that wonderful outpouring of light and heat which is the sun’s most prominent characteristic; and to this very day it has not been finally decided whether this luminosity proceeds from the sun’s solid body, or from an envelope which surrounds it. Indeed so strange and so unaccountable are many of the features presented to us, not only by our own sun, but by many of the stars, that it has even been conjectured that these bodies exhibit instances of the operation of forces of the nature of which we are yet ignorant. If we accept this view of the case, the study of our luminary becomes one of very great importance, but one in which we must be very careful to be guided by observation alone. We must obtain numerous and accurate representations of the sun’s surface, and study these carefully and minutely before we attempt to generalize.”
In the “Researches’ from which we have quoted, we find recorded no less than 631 groups of solar spots, which have been photographed at the Kew Observatory from March 11, 1858 to December 31, 1864. The value of such a continuous record as this can only be thoroughly understood by those who have given some careful attention to this class of phenomena. This is not the place to discuss the questions which have arisen with regard to the nature of solar spots. Still it is important that a general idea should be given of the conclusions to which Mr. De La Rue and other astronomers have arrived with respect to them.
It was first stated by Dr. Alexander Wilson, of Glasgow, in 1773, that certain phenomena appeared to indicate that spots are cavities in a luminous photosphere which surrounds the sun. Mr. Dawes has shown that we have often connected with the same phenomenon—the formation of a sun spot—not less than five degrees of luminosity:--1. the faculæ, or bright streaks of irregular direction; 2. the ordinary photosphere, the luminous envelope of the sun; 3. the penumbra, or shaded portion of a spot; 4. the borders of the umbra; and 5, the very dark central nucleus. The term umbra is used by Mr. Dawes to denote a region of a spot intermediate in darkness between the nucleus and that designated as usual by the term penumbra.
It should be understood that the photographs of the solar surface show with great distinctness those five degrees of illumination. Indeed these are so decidedly delineated on the collodion tablet, that, by calling in the aid of the electrotype process, Mr. De La Rue has been enabled to obtain plates, from which any moderate number of copies can be printed off.
The Kew photographs have already confirmed the results of some previous observations, and established some new and important facts. We have only space to state these as concisely as possible.
1. These photographs prove the central portion of the solar disk to possess a higher degree of luminosity than the borders.
2. They have shown that the umbra of a spot is nearer to the sun’s centre than the penumbra; that is, it is at a lower level. The solar spots are therefore cavities in the photosphere.
3. It appears fair to conclude, from the examination of all the sun-pictures in which the faculœ are copied, that “Solar faculæ consist of solid or liquid bodies of a grater or less magnitude, either slowly sinking or suspended in œquilibrio in a gaseous medium.
Another paragraph must, from its importance be quoted:--“The idea that faculæ are portions of the photosphere raised above the general surface, appears to be confirmed by stereoscopic pictures of spots obtained by Mr. De La Rue, where the faculæ often retain the same appearance for several days together, as if their matter were capable of remaining suspended for some time,”
The deduction to be drawn from a careful study of those solar autographs is, that the lower parts of a solar spot are of a lower temperature than the photosphere in which it is formed. Whether this is due, as some suppose, to the lower temperature of the body of the sun, or to matter coming from a colder region, as is more generally thought, remains yet to be determined.
Chacornac and Lockyer have recorded observations, on the behaviour of the matter surrounding a spot, which appear to suggest the existence of a downward current, which is therefore a current from the colder regions above. The faculæ in the larger number of examples fall behind the spots. This appears to suggest an ascending current carrying the hot matter behind. Thus possibly two currents are concerned in the formation of a sun-sport—if so, assimilating them to our terrestrial cyclones, which in many other respects they resemble.
The importance and the extension of this system of continuous observation must be evident to all; and it is satisfactory to know that a second heliograph has been made, under Mr. De La Rue’s direction, for the Russian Government, which is now erected at Wilna, the director of that observatory, Dr. Sabler, having received instruction at Mr. De La Rue’s observatory at Cranford.
On several occasions, at the Astronomical Society, Mr. Warren De La Rue ahs pointed out the advantages which will be derived from the use of photographic apparatus for recording future transits of Venus. In the words of the address on the presentation of the Lalande prize, we may bring our notice of Celestial Photography to a conclusion:--“By his own example, by giving instruction to others who desired it, and by continuous observations of his own, Mr. Warren De La Rue has been untiring in promoting astronomical photography; and it may be safely claimed for him that the bringing of this branch of science within the domain of calculation, marks a new era in practical astronomy.”