Our findings are corroborated by a historical discovery made by Dr Allan Sandage (Figure 123) in Pasadena:
However, there is evidence that Hubble indeed was aware of the 1920 paper at some time between 1920 and 1927. Remarkably, in the bound Volume 80 of the Monthly Notices that is in the Mount Wilson Observatory library in Pasadena, there are penciled notes in Hubble's handwriting in the margin of page 746 of the 1920 Reynolds paper placed beside the descriptions by Reynolds of his binning classes. Next to each of Reynolds class II, III and IV are the Sa, Sb and Sc notations penciled in by Hubble. Also in the margin is a penciled paragraph of notes. However, much of what is there has been erased, so that although one cannot read the notes, Hubble's Sa, Sb and Sc notations are there.
While these penciled notes are undated, the 1923 memo by Hubble (a copy of which was sent to Reynolds and which was signed by Reynolds) lays to rest a historical uncertainty unanswered up to the present time ... we can definitively say that Hubble had carefully read the Reynolds 1920 paper prior to writing his seminal 1926 work.
It remains a total mystery as to why Hubble makes no mention of the Reynolds classes in his preliminary classification discussion in 1922 or in his definitive 1926 paper; how amazing, in hindsight, to study the handwritten request of Hubble to Reynolds, to "throw your ideas into the form of a precise classification ..."
The kernel of the system by which astronomers continue to optically classify galaxies today was conceived in the mind of one of Britain's most gifted amateur astronomers - a man without any formal astronomical training - the great Mr. J.H. Reynolds of Birmingham.
Such was the profound respect held by astronomers of Reynolds' thoughts and writings, that he was a member of Commission 28, together with Slipher, Hubble and others.
The list of astronomers who corresponded with Reynolds included Eddington, Hertzsprung, Dyson, Hubble, Jeans, Shapley, Slipher, Smart, Milne - and scores of others.
Martin Johnson, who wrote Reynolds' obituary for the Royal Astronomical Society, recalls how "astronomers from many countries came to Birmingham to visit the Reynolds residence at Low Wood ... It is easy to recall scenes ... over many years ... Eddington, in Birmingham to give a lecture, ill and only kept on his feet by the skilled ministrations of Mrs. Reynolds, who is never dismayed by anything; Jeans ... Dyson ... Perhaps the most vivid picture is of de Sitter from Leiden, most fascinating of astronomers, arguing in the Low Wood music room about relativistic cosmology and his dislike of nineteenth century music, until Reynolds set out to convert him by playing the organ chorale-preludes which Brahms had written ..." The hospitality of Mr. and Mrs. Reynolds at their home at Low Wood was legendary, and some of the greatest astronomical minds of the age came to visit them. Figures 124 and 125 show Mr. Reynolds at meetings of the Club of the Royal Astronomical Society. In Figure 125 we see Mr. Reynolds at a dinner with the Danish astronomer Ejnar Hertzsprung, co-originator of the Hertzsprung-Russell diagram (a fundamental tool in the determination of the distances to stars).
To be immortalized in the minds of students of astronomy, Hubble (Figure 126) needed a diagram to depict his classification classes. As carefully explained by Allan Sandage:
In the dry academic language of formal science, and with so few working extra-galactic astronomers at the time (perhaps only 20 worldwide), without such a diagram there was the danger that the classification system, buried in the language of the Astrophysical Journal, might lay fallow.
Why did the diagram become so overwhelmingly important? Despite the excellence of Hubble's 1926 word descriptions of the classification, the diagram is much easier to understand and to remember. It became the visual mnemonic. Indeed, we all learned to classify from it. Only later did we read the verbal descriptions in the 1926fundamental paper. That was true in my generation. It is true now.
The British mathematical-physicist Sir James Jeans (Figure 127), one of the great populariz-ers of science of his time and a prolific author of popular books, such as The Universe around Us (1929), The Mysterious Universe (1930 and The Growth of Physical Science (1947), came to the rescue. At a meeting of the Royal Astronomical Society, there is a historic photograph (Figure 128) of Mr. Reynolds sitting in the Chair as President, with Sir James Jeans delivering a lecture.
To unravel the interplay between the works of Hubble and of Jeans, we purchased Jeans' books Astronomy and Cosmogony as well as Science and Music. In exploring the provenance of the diagram, full credit must be given to astronomy historian William Sheehan who acted as a master detective in this regard. It is abundantly clear that Jeans discussed the 1926 classification bins of Hubble and in 1929, Jeans used a Y-shaped fork diagram to graphically represent Hubble's scheme!
Historically, the roots of such detective work actually go back two decades, since there is a footnote in the book Man Discovers the Galaxies by Berendzen, Hart and Seeley (published in the early 1980s) that the original Y-shaped diagram may actually be found in Figure 53 of the book authored by Sir James Jeans entitled Astronomy and Cosmogony published in 1929.
To be historically accurate, Hubble failed to acknowledge two of his pivotal sources for those ideas which now bear his name: Reynolds and Jeans. As agreed by Allan Sandage, the graphical representation of the Hubble tuning fork must be attributed to Sir James Jeans - a scientist who adored music, and who wrote a famous book Science and Music on that theme.
In the Lowell Observatory archives, Hubble revealed to Slipher that he had "been trying to construct a classification of non-galactic nebulae analogous to Jeans' evolution sequence, but from purely observational material."
On theoretical grounds, Jeans predicted a sequence which was time dependent: starting off at early times from a rotating spherical cloud of gas which cools with time, to form, at much later epochs, a highly flattened disk. Jeans wrote: "After being at first almost spherical, it will become spheroidal, then will develop a sharp edge in the equatorial plane. Matter will then be shed off from this sharp edge and [start] describing orbits in the equatorial plane." Jeans envisaged spiral arms themselves to be ejected matter along the plane of the disk:
When first it assumes the lenticular form, the forces of gravitation and centripetal force do not suddenly become equal at all points ... Two
opposite points from the equator will be distinguished ... the rejected matter ought to form two symmetrical streamers or arms.
Hubble was deeply aware of the theoretical framework of Jeans, and of the degree of flattening envisaged by Jeans as time progressed. Hubble wrote:
Therefore the observer may well look to Jeans' theory for the thread of physical significance that shall vitalize a system of classification of non-galactic nebulae. In the scheme presently to be proposed, a conscious attempt was made to ignore the theory and to arrange the data purely from an observational point of view. The analogy however was so suggestive that at several points ... there was no hesitation in accepting the one favored by Jeans' theory of spirals.
Hubble was right to make a conscious attempt to ignore the theory. Although we still do not really understand how spiral galaxies change with time, it now seems likely that any such change is in the opposite sense to that envisaged by Jeans; that is, from Hubble's late to early types. Nevertheless, the concepts which Hubble used to describe his sequence of spiral galaxies into early and late types rested heavily on the work of Jeans, whose time sequence was from rotating spherical clouds at early epochs to flattened disks at later times.
Astronomers had used the terms "early" and "late" before Hubble and Jeans, in the context of the temperatures of star. In the early 1900s, some astronomers believed that the hot (so-called "early type") stars were young and gradually evolved into cooler "late type" stars. We now know that the situation is far more complex: both hot and cool stars can be young or old, and our Sun was not born as a hot star. Our Sun is currently a normal dwarf star but will progress with time into a cool red-giant star and eventually go through a very hot phase as it dies, with temperatures as high as 150 000 degrees Centigrade. (Astronomers categorize stars according to their intrinsic luminosity, or brightness; from highly luminous supergiant stars to intrinsically faint dwarfs and subdwarfs. The radius of a giant star is much larger than that of a dwarf star, while their masses may be comparable; the surfaces of giant stars are therefore characterized by gas densities and pressures that are low compared to those found in dwarf stars.)
The thinking in the early 1900s, from both a stellar and galactic viewpoint, was in terms of a sequence which progressed with time, from "early-type" to "late-type." It is curious that Hubble uses the terminology "early," "middle," and "late" type galaxies in his paper of 1926, and has a footnote which reads:
Terms which apply to series in general are available, however, and of these "early" and
"late" are the most suitable. They can be assumed to be a progression from simple to complex forms.
Those terms were indeed available - from Sir James Jeans' Problems of Cosmogony and Stellar Dynamics published in 1919.
Response to Hubble's 1923 memo was mixed. Writing from Helwan, Egypt on July 18, 1924, the astronomer Knox-Shaw expressed his thoughts to Slipher thus:
I found Hubble's note on the classification of nebulae especially interesting, and I am in general agreement with his proposals, though there are one or two points on which I should like to reserve my opinion ...
In a letter from the Harvard College Observatory dated October 8, 1924, Bailey wrote:
The terms Early, Middle and Late should not be emphasized, since the order ofevolution of these nebulae does not appear to be sufficiently well established at the present time, and it is undesirable to introduce theories into a classification, if it can be avoided (the underlinings appear on Bailey's
Prior to the 1923 Hubble memo, W.H. Wright at Lick Observatory, wrote a letter dated March 7, 1922, addressed to Slipher:
I must confess that I am rather dazed by the latter's [Hubble's] letter [dated February 23,1922] ... One can see that the nebulae will have no private life when he has his way... Besides my habit is to think from one plate to the next, and I am afraid lam not much on Empire Building; so I shall smooth your path by getting out of the way.
One week later, on March 14, 1922, Slipher replied to Wright:
Hubble's report dazed us too ... We know so little about nebulae today that it is no easy task to lay down a line of study that would be so good as not to need very vital alteration in even a few years time .
The International Astronomical Union Commission on Nebulae and Clusters held its meeting at Cambridge, England, in 1925, and objected to the fact that Hubble had seemingly proposed "terms suggestive of certain physical properties of the nebulae, about which there was still much doubt." His evolutionary scheme - with such terms as early, middle, and late - did not seem justified; instead the Committee recommended adoption of "a simpler system of a more purely descriptive nature
Figure 128  should be used."
Figure 128  should be used."
Reaction from Heber Curtis was also not favorable: "I also seriously question the wisdom of the use of the terms Early, Middle, and Late, as used by Hubble ..." wrote Heber D. Curtis in an undated document circa 1927. One year later, on April 22 1928, Curtis wrote to Slipher:
My own views as to any nebular classification are so at variance with those of many others who are now more actively engaged in actual work in this field that I think you had better simply "count me out", and put it down, - "one member of the Committee dissenting", or something like that.
A sad plea indeed, from the very person who first recognized the bar phenomenon in his phi-type galaxy. In the mind of Hubble, he was the custodian of morphological astronomy. Others, such as Knut Lundmark, presented similar (but not identical) classification schemes, but these were not published in the mainstream journals, and Hubble closely guarded his morphological terrain.
[Hubble] guarded its priority in a revealing footnote in part I ofhis 1926paper There he comments on a classification system proposed at about the same time by Lundmark (1926,1927). Some ofHubble's complaints, which he rarely made public, were unfounded, showing a sensitivity he generally kept hidden. Some ofHubble's accusations are addressed in a partially justifiably acerbic reply by Lundmark (1927), also in a footnote, in Lundmark's near great but largely neglected paper.
A portion of Lundmark's reply, contained in his "Studies of Anagalactic Nebulae" presented to the Royal Society of Science of Uppsala on May 6, 1927, reads as follows:
In his paper, E.P. Hubble makes an attack on me which is written in such a tone that I hesitate to give any answer at all ... I was not then a member of the Commission of Nebulae. I did not have any access whatsoever to the memorandum or to other writings of E.P. Hubble ... Hubble's statement that my classification Shrouds ofthe Night except for nomenclature is practically identical with the one submitted by him is
210 not correct [italics, those of Lundmark]. Hubble classifies his subgroups according to excentricity [sic] or form of the spirals or degree ofdevelopment while I use the degree ofconcentration towards the centre ... As to the three main groups, elliptical, spiral and magellanic nebulae it may be of interest to note that the two first are slightly older than Hubble and myself. The term elliptical nebulae thus is used by Alexander in 1852 and the term spiral by Rosse in 1845. The importance of the magellanic group has been pointed out by myself[Observatory, volume 47, page 277,1924] earlier than by Hubble. As to Hubble's way ofacknowledging his predecessors I have no reason to enter upon this question here.
Hubble's scientific achievements were grand. But on at least two accounts, Hubble was deeply inspired by the work of Reynolds. We have already discussed one of these at length: the Reynolds classification classes for spiral galaxies, published in 1920.
The second story is interesting, too: in 1913, Mr. Reynolds pioneered the measurement of the profiles of light across the bulges of spiral galaxies, beginning his investigation with the Andromeda Spiral Galaxy.
Reynolds had secured photographs of the Andromeda Galaxy with his 28-inch reflector at "Low Wood" in October 1912, and then measured the profile of light across its highly prominent bulge.
Using an instrument known as a "photomicrometer," supplied by Toepfer of Potsdam, Reynolds found that the light brightness decayed from the center, outward. Sandage calls this "the famous Reynolds profile" and notes that "Hubble (1930) later generalized [it] by making it scale free [dimensionless]." Today astronomers speak only of the Hubble luminosity profile - but why not the Reynolds (or, at least, the Reynolds-Hubble) luminosity profile? After all, it was Mr. John Reynolds who pioneered that work in 1913.
Mr. Reynolds was elected a Fellow of the Royal Astronomical Society of London in 1899, at age 25, served as Treasurer in 1929-1935 and President during the period 1935-1937.
Mr. Reynolds is one of the few persons ever to rise to the rank of President of the Royal Morphologist Extraordinaire
Astronomical Society, whose official occupation was not an astronomer. Reynolds was among 211
the last of the great amateur scientists. His technical skills in using photographic plates for quantitative intensity measurements were unsurpassed for the time and his vision has influenced generations.
In popular astronomical textbooks, we only read of the Hubble classification classes, the Hubble tuning fork and the Hubble luminosity profile for elliptical galaxies. Behind the stage loomed the giant Mr. Reynolds, a man whose name is almost unknown to students of astronomy.
Volume 80 of Monthly Notices of the Royal Astronomical Society, containing Hubble's penciled notes alongside the "highly neglected" 1920 paper by Reynolds is of exceptional historical value and no longer lies in the shelves of the Mount Wilson Observatory library in Pasadena; it has been removed, for safekeeping.
As fundamental as the Hertzsprung-Russell diagram is to stellar astronomy, so the Hubble tuning-fork has become a Rosetta stone in the classification of galaxies. Hubble presents the tuning-fork diagram in his famous book The Realm of the Nebulae (1936).
Astronomy textbooks will not change; the Hubble classification scheme and the Hubble tuning fork will continue to be taught to students worldwide; but may it be a source of much inspiration to younger readers that some of the grandest of ideas in the area of galaxy morphology did not spring forth from a professional astronomer trained at one of the world's prestigious Universities, but rather from the mind of Mr. John Henry Reynolds - a student of the heavens above - a gifted amateur who simply was passionate about the wonders to behold in the Night Sky, and who devoted a large sector of his energies and finances to spearheading new cosmic horizons. Although the 30-inch Reynolds telescope at Mt. Stromlo was totally destroyed by the bushfires which devastated sections of Can-Shrouds of the Night berra in January 2003, the building has been renovated and the legacy of Mr. Reynolds
212 (1874-1949) forever lives on.
The words spoken by E.J. Stone (President of the Royal Astronomical Society) upon presenting their Gold Medal to Mr. Andrew Common in February 1884 ring equally true for Mr. John Reynolds:
The amateur who can provide himself with sufficient instrumental means for original research need fear no professional rivalry; untrammeled by the necessity of continuing observations whose value largely depends on their continuity, having the power of taking up any subject he pleases, pursuing it so long as he believes in the possibility of success, without fear or responsibility of wasted time and wasted means, he possesses advantages which are priceless in the tentative and experimental stages ofany work ... It is in work of this class that the most striking advances in our science must be expected; and such work will most certainly repay, by the gratification of personal success, the efforts of those who devote themselves to original work in our science, and the field of research presented is absolutely priceless.
Why Hubble behaved in the manner he did, we will never know. Personal, intimate reflections by him are forever gone: personal notes destroyed after his death. Tragically, Hubble was a man with a mask. Few ever penetrated it.
"Every one is a moon, and has a dark side which he never shows to anybody," wrote Mark Twain. Perhaps the words below, also by Mark Twain, are appropriate:
It's just the way, in this world. One person does the thing, and the other one gets the monument.
Beneath these masks, different galaxies are lurking; new schemes of classification are waiting to be devised, not in the optical, but in the infrared regime, wherein we penetrate smoky and dusty Shrouds of the Night.
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