Eclecticism, Opportunism, and the Evolution
of a New Research Agenda:

William and Margaret Huggins and the
Origins of Astrophysics

by

Barbara J. Becker

A Dissertation submitted to The Johns Hopkins University
in conformity with the requirements for the degree of
Doctor of Philosophy
Baltimore, Maryland
1993


Copyright ©1993 by Barbara J. Becker
All rights reserved

 

CHAPTER 6—PART 1

SOLAR OBSERVATIONS AT TULSE HILL

From time to time throughout his career, William Huggins observed the sun. He had even played a significant role, as we saw in chapter 2, in resolving what came to be known as the "willow-leaves" controversy in the early 1860s, a heated dispute over the appearance and nature of the solar surface.1  In general, however, solar observation had not netted Huggins any prize discoveries or their attending prestige.  If anything, it had proven frustrating for him.

Recall from chapter 5 that some amateur astronomers, notably Alexander Strange, had publicly criticized Huggins for his failure to incorporate regular and systematic solar observations in his research agenda.  In Strange's view this failure meant Huggins was neglecting his obligation to use the equipment on loan from the Royal Society for the greatest good of the nation.  But, as we saw in chapter 3, routine solar observation had not been the charge given Huggins as part of the terms of the telescope loan, a loan which Strange himself had sanctioned as a member of the Royal Society's Council.  The Royal Society had presented the Grubb telescope to Huggins to pursue his agenda of stellar and nebular spectroscopy, an agenda to which Thomas Romney Robinson had referred at the time with great patriotic zeal.

There were, nevertheless, significant episodes in Huggins career, other than the willow-leaves controversy, during which solar observation became a principal object of his personal agenda.  The outcomes of Huggins' solar research efforts did not always match his expectations, however, and they are conspicuously missing from his retrospective account, "The New Astronomy."2  Huggins' biographers and historians of science have relied heavily on this essay for details of his life and career with the important consequence that Huggins has been remembered chiefly for his stellar and nebular spectroscopic research, while his solar research efforts have been all but forgotten.3

In this chapter, I shall bring to light three of William Huggins' unsuccessful forays into solar observation in order to give a more rounded picture of his endeavors.  I begin with his vain efforts in the late 1860s to observe solar prominences without an eclipse using both filtering techniques and innovative spectroscopic means.  Next, I examine in some detail the solar eclipse expedition to Algeria in December 1870, which Huggins led, and which was unfortunately clouded out.  Finally, I describe Huggins' lengthy efforts to photograph the solar corona without an eclipse, a challenging project he was motivated to pursue largely in consequence of the disappointment he experienced in Algeria.4

I shall argue that while solar observation was neither Huggins' forte nor his primary research interest, he was occasionally provoked by priority concerns to contribute to contemporaneous efforts to observe the sun spectroscopically just as solar observers like Lockyer were also drawn to stellar and nebular investigation. In the 1870s and 1880s, the discipline of astronomical physics was developing on many fronts and no one knew which would prove the most fruitful.  Ambitious and competitive pioneers like Huggins and Lockyer pressed the spectroscope into service in a variety of ways searching for discoveries and the recognition they promised.

Huggins' diverse investigations are documented in the pages of contemporary scientific journals.  But in his retrospective essay, Huggins eliminated those projects from his account which had either failed or did not fit directly into the story of the development of stellar spectroscopy.  The unpublished record brings these forgotten episodes to light once again, revealing how Huggins was motivated to modify his research methods and instrumentation in response to failure, as well as how he attempted to convince his colleagues of the validity of his observations in the face of doubt.  As we shall see in the pages that follow, Huggins' solar research efforts, despite their lack of success, played an important role in the development of method and theory in early solar physics.

The Red Flames

I briefly introduced, in chapter 3, Huggins' efforts to view the solar prominences without an eclipse as an example of his eclectic research program in the late 1860s.  In this section, I shall describe his work on the prominences in more detail, this time in the context of Huggins' growing awareness of the need to establish and carefully maintain his priority.

Solar prominences, or "red flames" as they were often called, had attracted the attention of solar eclipse observers since they were first described by Francis Baily after the total solar eclipse in 1842.5  Being limited to momentary glimpses of the red flames by the brevity of totality and the capriciousness of the attending weather made it difficult to obtain confirmatory observations.6  In 1860, Warren De La Rue had claimed success in photographing the near-solar atmosphere during totality.  He interpreted the images he had obtained as showing the limb of the moon sequentially occulting the flame-like protrusions, and thus convinced his fellow astronomers that the prominences were solar in origin rather than transient features in the terrestrial atmosphere or simply illusions brought on by the sharp contrast of dark and light.7  By the latter part of that decade, interest in the nature of solar prominences was again on the rise.

J. Norman Lockyer, for example, whose earlier astronomical interests had centered on the moon and the planet Mars, had turned his attention to the sun in the mid-1860s in part because of the excitement generated by the willow-leaves controversy.8  In March 1866, Lockyer began a spectroscopic study of sunspots using a clever method of his own design.  He projected the sun's image onto a screen with a slit.  The screen could be moved to position the slit across a sunspot. In this way a linear segment of the sunspot as well as a portion of the adjoining photosphere was thrown into the attached spectroscope allowing a comparison to be made of the two contiguous spectra.  An analysis of these observations formed the basis of his first paper submitted to the Proceedings of the Royal Society.9

Lockyer's paper entitled, "Spectroscopic Observations of the Sun," was communicated on his behalf by the Society's Secretary, William Sharpey on 10 October 1866, and read before the Royal Society at the 15 November meeting.  As we shall see, the dates are significant in terms of the dynamics of Huggins' and Lockyer's competitive relationship and the matter of priority in conceiving a plan to observe solar prominences without an eclipse.  Because of the priority dispute which later erupted over spectroscopic observation of prominences, the findings on sunspots Lockyer reported in his paper did not have the same enduring impact as his final suggestions for possible future applications of the spectroscope to solar research.  In particular, Lockyer's query, "and may not the spectroscope afford us evidence of the existence of the 'red flames' which total eclipses have revealed to us in the sun's atmosphere; although they escape all other methods of observation at other times?" later became a central point of contention.10  At the time he submitted the paper, Lockyer explained that his spectroscope did not provide him with sufficient dispersing power to render the prominence spectral lines visible without an eclipse.  He successfully applied to the Government Grant Committee of the Royal Society for funds to purchase a more suitable instrument.11

Nine of Huggins' 51 observations recorded in his notebook during 1866 were of the sun.  Recall from chapter 3 that 1866 was a year in which Huggins devoted time to a wide range of projects:  the nova in Corona Borealis, the great meteor shower, nebulae, and variable stars.  On the occasions that Huggins recorded observations of the sun, he reported examining surface features such as sunspots and granulation.  On 26 April, for example, he organized his notebook record as if he were starting a regimen of sunspot observations.  He divided his notes into headed categories like "distribution," "form," "size," and "brightness."  There is no other recording like this in the observatory notebooks in the Wellesley collection.

On 10 November 1866, one day after the regular monthly meeting of the Royal Astronomical Society, and not quite a week before the Royal Society meeting at which Lockyer's paper on solar spectroscopy was to be read, William Huggins wrote in his observatory notebook, "I tried a new method of endeavouring to see the red-flames" by a method that "had appeared to me probable (for some weeks)."12 The parenthetical remark here is telling.  But to whom was it addressed?  Huggins intended this entry to stand as evidence of priority in the quest for viewing the elusive solar prominences without an eclipse.  Clearly, he anticipated competition.

The method Huggins believed would render the prominences wholly visible to an observer and which he was then claiming to have been piecing together in his mind for some time is notable both for its originality and for the fact that it was not spectroscopically based.  Huggins reasoned that if, as reported, the prominences were red in color, it should be possible to filter out most other regions of the solar spectrum using a stack of differently colored pieces of glass held together with Canada balsam.  When he finally tried this approach in November 1866, however, it proved unsuccessful and Huggins seems to have dropped the project altogether for a time.  If the method for viewing the prominences had been in his mind "for some weeks" already, what motivated him to put it into action at this particular time? Perhaps Lockyer revealed something in informal conversation at the RAS meeting the night before to alert Huggins of his own interest in the matter.13

In August 1868, a total solar eclipse of over five minutes duration was predicted to cross a number of favorable sites in India and Malaya.14  Plans were made in Britain to mount expeditions to observe it.  By early 1867, in anticipation of the upcoming eclipse, George Stokes began gathering suggestions from his astronomer colleagues on ways of effectively analyzing the light from the red flames with a spectroscope.  Sir John Herschel sent some helpful advice.  In fact, he became so enthused with his own thoughts on the matter that he proceeded to suggest how such a method might be extended to permit observations of the solar prominences without an eclipse.  Herschel believed prominence spectra might prove to be so distinctive that it would be possible to detect their presence simply by comparing the spectrum of light emitted from the center of the sun with that from its limb.15

William Huggins wrote to Stokes with his recommendations for insuring successful spectroscopic observations of the prominences during the upcoming eclipse.  Huggins urged placing a skilled observer in charge of an equatorially mounted telescope of 3-3/4 inch aperture capable of being moved by hand.  It was Huggins' opinion that even with a competent observer, the limitations of expense imposed on a Government eclipse expedition would make it difficult to obtain more than the "general character of the spectrum of a red prominence, that is, whether it be continuous, or consist of bright lines."16

Six months before the eclipse, in the February 1868 number of the Monthly Notices, Huggins disclosed, in his annual observatory report, that he had tried to view solar prominences without an eclipse.17  In this report, he made no mention of trying to make the red flames visible by filtering the sun's rays through a stack of colored glass plates.  Instead, he described a spectroscopic method drawn from his experience with nebular spectra.  Huggins reasoned that if prominences were gaseous, they would display an array of bright emission lines when viewed spectroscopically.  These colorful lines would suffer little dispersion in consequence of their passage through a prism, regardless of its power, and hence would barely show any diminution in brilliance.  Other light near the prominence, from the background sky, for example, or the solar limb, already known to produce a broad Fraunhofer spectrum could be significantly reduced in intensity by passing it through a prism of great dispersive power.  In this way, a prominence spectrum could be seen distinctly.

Huggins claimed to have been engaged in making such observations for the past two years.  While this was a bit of an exaggeration, it sufficed to establish him as a serious contender for priority in this limited arena.18  In fact, since, in early 1868, Lockyer was still awaiting the completion of his new and more powerful spectroscope, Huggins had an instrumental edge on him.  But Huggins' notebook entries show he was pre-occupied in 1867 with his experiments designed to measure the heat of celestial bodies, observing changes in the lunar crater Linné, and, by 1868, beginning his measures of stellar motion in the line of sight.  During this particular two year period, Huggins recorded very few solar observations and almost all of these were observations of sunspots.19

As the August 1868 eclipse approached, two British and two French teams equipped for spectroscopic, photographic, and visual observation were sent to India and Malaya.  Clouds obscured the beginning of totality at Jamkandi where one of the British teams headed by Lieut. John Herschel, son of astronomer Sir John F. W. Herschel, was waiting to observe spectroscopically any prominences that might be visible.  Fortunately, the clouds cleared sufficiently during totality for Herschel to glimpse the spectrum of a prominence.20  The sight of the bright lines sparked an idea for a method of monitoring prominences on a regular basis, a method relying on intervening absorptive media very similar to that devised by Huggins nearly two years earlier.  Lieut. Herschel wrote to his father:

It has occurred to me that, since the whole light of the "flames" is of three refrangibilities only (or nearly so), dark glasses (could they be formed) which allowed these only to pass, would so enormously diminish the light from the Solar disk, as to enable the flames to be seen without the interposition of an opaque body, i.e. without an eclipse....  Is the idea a practical one?  If it is, these flames may come to be studied at leisure!21

The second British team, headed by Major John Tennant and stationed at Guntoor, was hindered by cloud cover during the second half of totality.  One team member, specially trained in advance by Warren De La Rue, took charge of obtaining a set of photographs during totality in continuation of De La Rue's efforts during the 1860 eclipse.  The team obtained six faint, but, in their opinion, satisfactory photographs of the solar atmosphere during totality which showed considerable detail in the structure of the visible prominences.  Tennant's spectroscopic observations of the prominences were thwarted by a recalcitrant clockdrive, although he noted seeing several bright lines in their spectra which he believed were coincident with some of the Fraunhofer lines in the solar spectrum.

Pierre Jules Janssen, France's pre-eminent solar observer, led his country's eclipse expedition to Guntoor.  The French team trained in advance to handle the mental and physical pressures of the work to be done during totality.22  Before clouds obscured his view of the eclipsed sun, Janssen was able to subject two large solar prominences to spectroscopic examination.  The bright lines he observed led Janssen to conclude that the prominences were gaseous in nature.  He also surmised, when he saw how vividly bright the lines were, that they might remain visible under spectroscopic scrutiny even in full sunlight, just as Huggins had suggested independently several months earlier.  Janssen tested his hypothesis the next day. Remembering the approximate location of the larger prominences on the solar limb, he quickly detected their bright lines.23

Meanwhile, Lockyer was still awaiting the completion of the new spectroscope being made for him by John Browning.  He had had, however, the opportunity to become acquainted with some of the eclipse observers' cabled reports.  Although Lockyer seems to have been ignorant of Janssen's discovery, he knew that others had confirmed the suspicion that the prominences produced bright line emission spectra.  The qualitative nature of these observations did not provide Lockyer with sufficient information to allow him to know which spectral lines to look for, but at least he was given hope that they would be visible.24  On 19 October 1868, just days after obtaining his new spectroscope, Lockyer observed carefully the bright line spectrum of a prominence.25  He sent out letters immediately describing his preliminary findings.  Because of the delay in receiving any word from Janssen regarding his own discovery back in August, Lockyer's announcement arrived at the Académie des Sciences in Paris at virtually the same time as Janssen's.  Lockyer and Janssen were awarded a special medal by the French government in honor of their independent discoveries.  No official recognition, however, was bestowed on either man by the British scientific societies.26

Huggins did not see the bright spectral lines produced by a solar prominence until 19 December 1868, fully two months after Lockyer's success.  He failed in spite of the fact that, as we have seen, he had suggested a means of direct observation of the solar prominences without an eclipse back in February 1868.  He had the necessary instrumentation.  In fact, when he ultimately viewed the solar prominences for the first time, he tells us that he did so with his trusty spectroscope which boasted two dense 60° prisms by Hofmann and Ross:

Applied 2 prism spectroscope to edge of sun.  Saw at once the three bright lines.  The red very strong.  The F line like this [diagram] broader at the base.  The line near D apparently double, not certain of this, a little more refrangible than D.  Tried red glass, but could not see prominence.27

Huggins' acquaintances were puzzled as to why he had been unable to see the spectral lines until then.  In November 1868, Warren De La Rue wrote to George Stokes:

It is curious that Huggins should have failed in discovering the "red flame" -- because he is a very skilful observer: -- had he been successful he would have anticipated Janssen and, by so doing, rendered great assistance to the Eclipse observers.28

Agnes Clerke would later conclude that Huggins "devised various apparatus for bringing them into actual view; but not until he knew where to look did he succeed in seeing them."29  This was a harsh verdict for an observer who, by the time Clerke handed it down, had achieved considerable respect for his care and perspicacity.30

Huggins knew from his own experience that "fishing around the limb of the sun," as Lockyer so aptly put it, for elusive emission lines was a hit or miss activity.31  An individual who had seen the lines during an eclipse would be better prepared, but "not knowing what kind of lines would appear in the prominences,"32 or where to expect them, he remonstrated, "it would have been by accident only if I had succeeded in obtaining a view of the flames."33  Huggins' insinuation that Lockyer had succeeded principally because he had some knowledge of the recent eclipse observations was not lost on Lockyer who angrily denied that he had been helped in any way by the findings of the 1868 eclipse observers.  Lockyer pointed to his 1866 Proceedings paper as evidence that he had been working toward just such a discovery on his own for two years.  John Browning and Balfour Stewart came to Lockyer's defense.  Huggins was unconvinced and unrepentant.34

Huggins felt that once eclipse observers had definitively resolved the question of the character of prominence spectra and described where to look, actually seeing the spectral lines without an eclipse was merely a technical exercise, not a major discovery.  Clearly, Janssen had beaten everyone to the visual discovery.  But any skilled observer with the right information and sufficient instrumental power could have done that.  What really counted was figuring out that it could be done in the first place.  And on that score, Huggins believed he had beaten them all.  Lockyer may have had plans to examine the prominences spectroscopically in October 1866 -- but what were they?

Meadows has discussed the substance of this quarrel.  Further recounting of details here is unnecessary.  Suffice it to say that Lockyer continued to seethe long after the fact.35  And Huggins, through his role in the dispute, became more aware of the need to establish and preserve his priority whenever he engaged in some research project he believed to be original.  Astronomical physics was evolving rapidly and one's priority required constant reassertion.  Investigators were provided with no clear boundaries or well-defined research guides.  What might seem peripheral at one time could prove to be central at another.  Thus, in February 1869, Huggins submitted a paper to the Royal Society's Proceedings describing his earlier thermometric work to preempt others' claims.36  And, when Warren De La Rue published what he thought was a new method of observing the whole of a prominence without an eclipse by using only absorptive filtering, Huggins responded quickly, claiming he had already thought about that "three or four years since."37

In summary, the development of a successful method of rendering the solar prominences visible to observers on any cloudless day had extremely important implications for solar observers.  Prominences could now be monitored on a regular basis just like sunspots without waiting for an eclipse, without begging for funds to sponsor an expedition, and without praying for clear skies during totality. Prominence activity could also be examined on the visible surface of the sun instead of just at the sun's limb.  When reports from all the 1868 eclipse observing stations had been gathered, there were hints that prominences were active solar features that could and did change in structure and appearance over very short periods of time. Near the close of the RAS meeting in January 1869, which was devoted almost entirely to discussion of the 1868 eclipse, Warren De La Rue observed:  "It comes to this, that the spots are the least frequent occurrences.  The changes of the faculae and prominences are much more numerous."38

Astronomical physics itself was changing even more quickly.  It was becoming almost necessary for investigators, like the Red Queen, to run merely to stay in place.  The September 1869 number of the Astronomical Register opened with the statement, "The age is essentially a fast one....  [W]ith regard to our present subject [spectroscopic observations of the sun] ... the race for fresh discoveries is so evident and the competition among observers so keen."39  The lack of rigidity in Huggins' research program served him well here.  His early attempts to view solar prominences without an eclipse, in spite of his lack of success, gave him the opportunity to play a central role in the ensuing priority dispute.  Instead of sitting on the sidelines as a nebular and stellar specialist, Huggins chose to jump into the fray with the solar observers.

NOTES
[click on footnote number to return to text]

1. See C. F. Bartholomew, "The Discovery of the Solar Granulation," Quarterly Journal of the Royal Astronomical Society 17 (1976):  263-89.

2. William Huggins, "The New Astronomy:  A Personal Retrospect," The Nineteenth Century 41 (1897):  907-29.

3. A notable exception is A. J. Meadows in Early Solar Physics (Pergamon Press:  Oxford, 1970).  Although Meadows chose not to include any of Huggins' papers in the appended collection of original papers on solar research, Chapter 2 on "The New Astronomy" contains numerous references to Huggins' solar work ranging from his early examination of sunspots through his efforts to photograph the solar corona without an eclipse.  Anstis discusses briefly Huggins' work on the solar corona (see, Anstis, "Scientific Work," 194-6).  While Hufbauer lists Huggins as one of a handful of early pioneers in solar physics, he provides no further information on his contributions (see, Exploring the Sun, 60).

4. A. J. Meadows discusses Huggins' role as one of the first to observe solar prominences using a spectroscope in his Science and Controversy:  A Biography of Sir Norman Lockyer (MIT Press:  Cambridge, 1972):  54-7.  Alex S. Pang, in his recent dissertation on British solar eclipse expeditions ( Spheres of Interest: Imperialism, Culture, and Practice in British Solar Eclipse Expeditions 1860-1914, Ph.D. dissertation, University of Pennsylvania, 1991), omits the plans and efforts of Huggins' solar eclipse team which was dispatched to Oran in 1870, perhaps because the expedition was confounded by clouds.

5. Francis Baily, "Some Remarks on the Total Eclipse of the Sun, on July 8th, 1842," Monthly Notices of the Royal Astronomical Society 5 (1839-1843):  208-14; 212-3.  The drawing of the sun at totality (located opposite page 212) was reproduced in two colors to provide some indication of the color and appearance of what Baily referred to as "protuberances."  He noted their "colour was red, tinged with lilac or purple; perhaps the colour of the peach blossom would more nearly represent it.  They somewhat resembled the snowy tops of the Alpine mountains, when coloured by the rising or setting sun."

6. The desire to view the prominences of the sun without having to wait for an eclipse led astronomers to try to find some way to obscure their view of the central disk of the sun in order to reveal the fainter features at the solar limb.  Airy recounted cutting a hole in a screen to match precisely the size of the image of the solar disk.  That way the brilliance of the disk's image would not interfere with the prominences that were expected to appear arrayed around the hole's circumference. Airy had no success with this method.  Charles Piazzi Smyth also failed in a similar trial during his expedition to Tenerife in the late 1850s.  See, discussion following Huggins' presentation of his paper, "On a possible Method of viewing the red Flames without an Eclipse," Astronomical Register 7 (1868):  263-5; 264.

7. De La Rue's 1860 eclipse photographs were highly regarded by his fellow astronomers as a significant achievement in both celestial photography and solar astronomy.  See, Robert W. Smith, "The Heavens Recorded:  Warren De La Rue and the 1860 Eclipse," paper given at the XVIth International Congress of the History of Science (Bucharest, 1981).

8. Meadows, Science and Controversy, 44-7.

9. J. Norman Lockyer, communicated by Dr. Sharpey, "Spectroscopic Observations of the Sun," Proceedings of the Royal Society 15 (1866):  256-8. Lockyer's paper was communicated by his friend, William Sharpey, because Lockyer was not yet a Fellow of the Royal Society.  He was elected in 1869.

10. Ibid., 258.

11. Lockyer was granted £40 by the Committee in 1867 to obtain a better spectroscope.  See, "Account of the appropriation of the sum of £1000 annually voted by Parliament to the Royal Society (the Government Grant), to be employed in aiding the advancement of Science," Proceedings of the Royal Society 19 (1870): 135-45; 142.  Lockyer commissioned Thomas Cooke to make his spectroscope in January of that year, but Cooke was otherwise engaged.  Cooke's inability to complete the project in a timely manner forced Lockyer to hand over the incompleted spectroscope project to John Browning in January 1868.  Browning's slow work pace and Lockyer's ill-health conspired to prevent Lockyer from trying his new instrument until October 1868.  See, "Spectroscopic Observations of the 'Red Prominences' without an Eclipse of the Sun," in Report of the Council, Monthly Notices of the Royal Astronomical Society 29 (1869):  162-3.  Meadows provides a good discussion of this sequence of events although he mistakenly ascribes Lockyer's change of instrument makers to Thomas Cooke's death.  Cooke died on 19 October 1868, months after the project had been handed over to Browning, and ironically the very day Lockyer first succeeded in seeing the prominences out of eclipse with his new instrument fashioned by Browning.  See Meadows, Science and Controversy, 52-3; [Charles Pritchard], "Thomas Cooke," Monthly Notices of the Royal Astronomical Society 29 (1869):  130-5.

12. William Huggins, 10 November 1866, Notebook 2.

13. The informal minutes of the meeting published in the Astronomical Register shows most attention was directed to the upcoming meteor shower and reports of spectroscopic observation of the nova in Corona Borealis.  Given that Lockyer's paper on observing solar prominences was due to be read before the Royal Society in less than a week, Lockyer would have wanted to assure that it was not prematurely announced at the RAS.  Even though he would not have discussed the matter formally, he may have mentioned it privately.

14. Major Tennant brought this eclipse to the attention of his fellow amateurs in 1867.  See, Tennant, "On the Solar Eclipse of 1868, August 17," Monthly Notices of the Royal Astronomical Society 27 (1867):  79.

15. John Herschel to George Stokes, 5 May 1867, in Memoir and Scientific Correspondence of the Late Sir George Gabriel Stokes, Volume I, Joseph Larmor, ed. (Cambridge University Press:  Cambridge, 1971; 1907):  211.

16. William Huggins to George Stokes, 15 May 1867, Stokes papers, Add MS 7656.H1112, University of Cambridge Library.

17. "Mr. Huggins' Observatory," Report of the Council, Monthly Notices of the Royal Astronomical Society 28 (1868):  86-8.

18. As noted in chapter 3, Huggins' first attempt to observe the solar prominences out of eclipse took place on 10 November 1866.  At that time he remarked that he was trying to accomplish this feat using a new method which he had been thinking about for several weeks.  Given his phrasing, there can be no question that it describes the beginning of his efforts on this particular project. Without access to his private notebooks, Huggins' contemporaries could neither confirm nor refute his claim.

19. Huggins recorded solar observations on 31 May, 2, 8 and 27 November, and 5 December 1867; and 6 February, 15 April, and 19 December (at which time he recorded his own first sighting of a prominence out of eclipse) 1868.  See Notebook 2.

20. Herschel was in a very excited frame of mind during this eclipse.  The anticipation of the great responsibility he had assumed, the thrill of the first moments of totality and the intermittent cloud cover which threatened the success of the entire operation resulted in measures being made of only three of the bright lines he observed in the solar prominence.  See his remarks in "The Great Eclipse of the Sun, I," The Engineer 6 (1868):  345-6.

21. Lieut. John Herschel to Sir John Herschel, 2 September 1868, cited in Sir John Herschel, "On a possible Method of viewing the Red Flames without an Eclipse," Monthly Notices of the Royal Astronomical Society 29 (1868):  5-6.

22. Janssen later wrote:  "The decisive moment drew near, and we waited for it with great anxiety.  This however, did not affect our intellectual powers:  they were rather over-excited, and this feeling was amply justified by the grandeur of the phenomena nature had prepared for us, and by the knowledge that the fruits of our great preparations and a long voyage depended entirely upon the observation of some moments' duration."  See, M. Janssen, "The Total Solar Eclipse of August 1868, Part I," Astronomical Register 7 (1869):  107-110; 108-9.

23. P. J. C. Janssen to the Permanent Secretary of the Académie des Sciences, 19 September 1868, translated and reprinted in Meadows, Early Solar Physics, 117-8; Pierre Jules Janssen, "Summary of Some of the Results obtained "The Total Solar Eclipse of August 1868, Part II," Astronomical Register 7 (1869):  131-4; 131.

24. Meadows, Science and Controversy, 54-5.  As Meadows points out, this information may have been critical since Lockyer had recently begun to express doubt in the gaseous nature of the prominences.  See, Balfour Stewart and J. Norman Lockyer, "The Sun as a Type of the Material Universe, I and II," Macmillan's Magazine 18 (1868):  246-57 and 319-27; 254.

25. Lockyer made the important discovery that the bright yellow line attributed by some observers to the close pair of solar D lines (associated with sodium), was not in fact coincident with them.  After considerable study, Lockyer later contended that this line, the so-called D3 line, was produced by an as yet undiscovered element.  (Lockyer became so convinced of this assertion that he named the unknown element.  He chose to call it "helium" because the source of the D3 spectral line seemed abundant in the sun, although its presence had thus far escaped detection in terrestrial samples.  Only years later was helium identified by the chemist, William Ramsay, as a natural emanation from the mineral clevite.) Lockyer also announced the discovery of a new thin layer of solar atmosphere which he called the "chromosphere" for its bright pink color.  Both of these claims aroused considerable discussion.

26. As mentioned earlier, Lockyer -- though placed in nomination for the Royal Astronomical Society's prestigious Gold Medal in 1871 for his work in solar physics -- failed to receive the three-quarters majority required.

27. William Huggins, 19 December 1868, Notebook 2.

28. Warren De La Rue to George Stokes, 23 November 1868, Stokes papers, Add MS 7656.D200, University of Cambridge Library.

29. Agnes M. Clerke, A Popular History of Astronomy during the Nineteenth Century, 2nd ed., (Macmillan & Co.:  New York, 1887):  215.

30. Recall also that, as described in Chapter 3, during this critical period Huggins was distraught over the death of his mother and extremely anxious about arrangements to obtain a new telescope.  A lack of concentration resulting from these two factors may have been partially responsible for Huggins' lack of success, but Clerke's assessment is, by and large, on the mark.

31. For Lockyer's remarks, see the published notes from the animated discussion on solar prominence observation which took place at the 13 November 1868 RAS meeting following William Huggins' presentation:  "On a possible Method of viewing the red Flames without an Eclipse" in Astronomical Register 6 (1868): 263-5. 264.

32. Ibid., 265.

33. William Huggins, "On a possible Method of viewing the Red Flames without an Eclipse," Monthly Notices of the Royal Astronomical Society 29 (1868):  4-5.

34. See discussion following J. Norman Lockyer, "Note on a Paper by Mr. Huggins," Astronomical Register 7 (1869):  42.

35. Consider this excerpt from a letter from Lockyer to George Stokes in August 1869:  "As I know how far & wide what you say will be read I take the liberty of sending you a tirage à part [he meant " tiré à part," an offprint] of one of my papers, showing that Hydrogen was not so obviously indicated by the Eclipse observers as Mr. Huggins stated it to be when he attempted to take a good part of the credit due to Janssen & myself working without an eclipse away from us."  J. Norman Lockyer to George Stokes, 14 August 1869, Add MS 7656.L558, Stokes papers, University of Cambridge Library.

36. Huggins' brief announcement of his intention to publish a paper on this topic prompted E. J. Stone, First Assistant at Greenwich, to remark that he had begun a similar program of research and had, in fact, recently purchased some expensive apparatus to carry out this program unaware of Huggins' earlier efforts.  See William Huggins, "Note on the Heat of the Stars," Proceedings of the Royal Society 17 (1869):  309-12; E. J. Stone, "Approximate determinations of the Heating-Powers of Arcturus and a Lyrae," Proceedings of the Royal Society 18 (1869):  159-65.

37. Here again, Huggins exaggerates somewhat in dating his work on solar prominences by inferring it took place somewhere between 1865 and 1866 rather than at the end of 1866.  See Warren De La Rue, "On some Attempts to render the Luminous Prominences of the Sun visible without the use of the Spectroscope," Monthly Notices of the Royal Astronomical Society 30 (1869):  22-4; William Huggins, "Note on Mr. De La Rue's paper 'On some attempts to render the luminous prominences visible without the use of the Spectroscope'," Monthly Notices of the Royal Astronomical Society 30 (1869):  36-7.

38. Meeting of the Royal Astronomical Society, January 8, 1869, Astronomical Register 7 (1869):  35-45; 44.  The suggestion that prominences change with great rapidity was soon withdrawn, however, when it was discovered that the changes observed were due to faulty alignment of sequential eclipse photographs.

39. "Spectroscopic Observations of the Sun. I," Astronomical Register 7 (1869): 193-6.


TABLE OF CONTENTS

William Huggins' Early Astronomical Career

  • Chapter 2—

Unlocking the "Unknown Mystery of the True Nature of the Heavenly Bodies"

The Astronomical Agenda:  1830-1870

"A sudden impulse..."

Reception of Spectrum Analysis Applied to the Stars

  • Chapter 3—

Moving in the Inner Circle

Cultivating Advantageous Alliances; Opportunism and Eclecticism

Opportunism and Eclecticism (continued)

Achieving "A mark of approval and confidence"

  • Chapter 4—

Margaret Huggins: The myth of the "Able Assistant"

The Solitary Observer

Celestial Photography

Diversity and Controversy: Defining the Boundaries of Acceptable Research

  • Chapter 6—

Solar Observations at Tulse Hill

    • Part 1—

The Red Flames

The Eclipse Expedition to Oran

Photographing the Corona Without an Eclipse

The Bakerian Lecture