IV. SOME PHYSICAL LABORATORIES AND PHYSICAL PROBLEMS
SIR NORMAN LOCKYER AND SOLAR CHEMISTRY
SIR NORMAN LOCKYER is professor of astronomical physics and director of the solar observatory at the Royal College of Science in South Kensington. Here it is that his chief work has been done for some thirty years past. The foundation-stone of that work is spectroscopic study of the sun and stars. In this study Professor Lockyer was a pioneer, and he has for years been recognized as the leader. But he is no mere observer; he is a generalizer as well; and he long since evolved revolutionary ideas as to the origin of the sidereal and solar systems.
For a man whose chief occupation is the study of the sun and stars, smoky, foggy, cloudy London may seem a strange location. I asked Professor Lockyer about this, and his reply was most characteristic. "The fact is," he said, "the weather here is too fine from one point of view: my working staff is so small, and the number of working nights so large, that most of the time there is no one about to do anything during the day. Then, another thing, here at South Kensington I am in touch with my colleagues in the other departments—physics, chemistry, and so forth—and can at once draw upon their special knowledge for aid on any obscure point in their lines that may crop up. If we were out in the country this would not be so. You see, then, that it is a choice between weather and brains. I prefer the brains."
Professor Lockyer went on to state, however, that he is by no means altogether dependent upon the observations made at South Kensington. For certain purposes the Royal Observatory at Greenwich is in requisition, and there are three observatories at different places in India at which photographs of the sun-spots and solar spectra are taken regularly. From these combined sources photographs of the sun are forthcoming practically every day of the year; to be accurate, on three hundred and sixty days out of the three hundred and sixty-five. It was far otherwise when Professor Lockyer first began his studies of the sun, as observations were then made and recorded on only about one-third of the days in each year.
Exteriorly the observatory at South Kensington is not at all such a place as one might expect to find. It is, in Professor Lockyer's own words, "little more than a collection of sheds," but within these alleged sheds may be found an excellent equipment of telescopes, both refracting and reflecting, and of all other things requisite to the peculiar study which forms the subject of special research here.
I have had occasion again and again to call attention to this relatively meagre equipment of the European institutions, but in no case, perhaps, is the contrast more striking between the exterior appearance of a famous scientific institution and the work that is being accomplished within it than is shown in the case of the South Kensington observatory. It should be added that this remark does not apply to the chief building of the Royal College of Science itself.
The theories for which Professor Lockyer has so long been famous are well known to every one who takes much interest in the progress of scientific ideas. They are notably the theory that there is a direct causal association between the prevalence of sun-spots and terrestrial weather; the theory of the meteoritic origin of all members of the sidereal family; and the dissociation theory of the elements, according to which our so-called elements are really compounds, capable of being dissociated into simpler forms when subjected to extreme temperatures, such as pertain in many stars. As I have said, these theories are by no means new. Professor Lockyer has made them familiar by expounding them for a full quarter of a century or more. But if not new, these theories are much too important to have been accepted at once without a protest from the scientific world. In point of fact, each of them has been met with most ardent opposition, and it would, perhaps, not be too much to say that not one of them is, as yet, fully established. It is of the highest interest to note, however, that the multitudinous observations bearing upon each of these topics during the past decade have tended, in Professor Lockyer's opinion, strongly to corroborate each one of these opinions.
Two or three years ago Sir Norman Lockyer, in association with his son, communicated to the Royal Society a paper in which the data recently obtained as to the relation between sun-spots and the weather in India—the field of observations having been confined to that territory—are fully elaborated. A remarkable feature of the recent work in that connection has been the proof, or seeming proof, that the temperature of the sun fluctuates from year to year. At times when the sun-spots are numerous and vigorous in their action, the spectrum of the elements in these spots becomes changed. During the times of minimum sun-spot activity the spectrum shows, for example, the presence of large quantities of iron in these spots—of course in a state of vapor. But in times of activity this iron disappears, and the lines which previously vouched for it are replaced by other lines spoken of as the enhanced lines of iron—that is to say, the lines which are believed to represent the unknown substance or substances into which the iron has been decomposed; and what is true of iron is true of various other elements that are detected in the sun-spots. The explanation of this phenomena, if Professor Lockyer reads the signs aright, is that during times of minimum sun-spot activity the temperature of the sun-spots is relatively cool, and that in times of activity the temperature becomes greatly increased. One must come, therefore, to speaking of hot spots and cool spots on the sun; although the cool spots, it will be understood, would hardly be considered cool in the terrestrial sense, since their temperature is sufficient to vaporize iron.