the solution will be considered ended, and some of the relations sought for are certainly obscure. But all must admire the excellent work done by Mr. Elvins, and the true scientific spirit in which he pursued it.

From the first of the above-quoted letters it will be seen that Mr. Ashe rejected the so-called 'cavernous' theory of sun spots, which was first explicitly stated by Wilson (1774), and afterwards developed in detail by W. Herschel, and favored the view that the spots were due to the descent upon the sun of meteoric matter. Mr. Elvins also supported this theory and discussed it at some length in one of a series of papers published in The Canadian Magazine, a periodical which was edited by his friend Ridgway, and which lived only seven months, July, 1871, to Jan., 1872. There were six papers in all and they bore the general title, "The Sun and the Worlds around Him." The first three dealt with the appearance and constitution of the sun; the next two, with the connection between sun spots and terrestrial phenomena; and the last one, with Mercury, Venus and the earth. They showed a good knowledge of the scientific literature on the subject and were written in a clear and pleasing style. The papers were printed under the pen-name "Omicron", and Mr. Elvins informed the present writer that he did not use his own name for fear his employers would complain that he was not giving his undivided attention to the business, although it would appear, from Mr. Ashe's second letter, that he devoted twelve hours a day!

As I have said, Mr. Elvins favored the view that sun spots were caused by the deposition of meteoric matter on the sun, but he was not satisfied with a simple vague statement of the theory. He wished to give it definiteness, so as to be able to secure evidence either to support or to disprove it.

Now, in 1863, Carrington had published his famous work on sunspots in which, amongst other results, he proved that the spots have a proper motion in a direction opposite to the direction of rotation, and that the spots near the pole are longer visible on the sun's disc during a rotation than those near the equator; and in 1867 Adams had deduced the orbit of the November meteors, with

a period of about 334 years; also it had been shown that the mean interval between sunspot maxima was about 11 1/9 years.

Mr. Elvins thought he could obtain from Carrington information which would decide whether his theory was valid or not, so on June 24, 1870, he addressed to him a long and well composed letter, a copy of which has been preserved. He asked Carrington to answer the following question:

Does the rate of the proper motion of sunspots remain unchanged, from the time when they first appear, to the time when they cease to be visible? Some spots have been seen for a long time, during which the sun has made several rotations; in such cases have not the spots passed over the sun's disc in less time during the latter part of the spot's existence than during the former part?

Then, after reviewing several theories put forward to explain the production of the spots and their peculiar motions, he gives his theory, that they are due

to meteors revolving in a large elliptical ring having the sun in one of its foci, with the aphelion beyond the orbit of Uranus; having three portions more densely crowded together than the intervening parts, and revolving in about 33 years; that this ring is composed in part of our November meteors, and that the November meteoric orbit is in fact the orbit in which the meteors move which cause sun-spots, but that it is comparatively a narrow, flat ring, like Saturn's, and contains meteors of every size, from the very smallest to the largest meteorites; and these are precipitated on the sun by the disturbing influence of the planets. This theory meets every difficulty and explains all the facts.

He then elaborates the theory, and he thinks that if the spots are due to the falling of meteorites, these meteorites should lose their momentum as time went on, and so the proper motion of the spots during any rotation should be less than during a preceding

one.

Carrington's reply is dated at Churt, near Farnham, 1870, July 25, and he quotes the cases of eleven spots seen during three rotations, from which it appears that there were about as many cases of increase as of decrease of velocity. Thus this evidence. was unfavorable to Mr. Elvins's theory.

At the present time the meteoric theory has been pretty

definitely rejected, and so also has been the 'cavernous' view as originally stated. From investigations with the spectroheliograph, it would appear that there is a hollow, but it may be in a distinct table-land on the sun's surface, and the depression is masked by overhanging clouds.

In addition, there was interesting correspondence with W. T. Lynn, of the Greenwich Observatory, on the period of the November meteors and of sunspots; with W. H. Pickering, on the moon ; with Daniel Kirkwood, for many years his friend, on rain-fall statistics and other matters; with T. J. J. See, on the capture theory of comets and on the moon's motion; and with others. Dr. See, under date March 20, 1910, writes: "I have already adopted your suggestion about streams of dust interfering with the motion of the moon. This must produce some effect, and it may explain the outstanding difficulty." These letters exhibit the activity of Mr. Elvins's mind, which was full of hypotheses and was always seeking to correlate and explain natural phenomena.

In 1872-3 Mr. Elvins published in The Toronto Leader a series of letters on the "Origin of the Solar System". He could not accept the Laplacian nebular hypothesis in its ordinary form, chiefly on geological grounds. As usual, the letters were written in a flowing, lucid style and exhibited wide reading and much thought. He elaborated a theory in which the successive steps are: "The sun throws off rings; rings form worlds; worlds move. outward from the sun; they increase in temperature; they throw off rings which form satellites; these move outward until the force of their primaries is overpowered by opposing forces; they take new orbits, long ellipses, pass round the sun as meteors and comets, and finally fall into the sun again". Though carefully reasoned out, I believe the theory dynamically unsound and the conclusions invalid. No satisfactory substitute for the Laplacian. theory has yet been found.

In 1874 Mr. Elvins had another series of letters in The Toronto Leader. Professor J. M. Hirschfelder" had delivered,

"Jacob M. Hirschfelder was Professor of Oriental Languages from 1847 to 1888, first in King's College and then in University College, into which it was changed. He died in 1892, aged 83 years.

and then published, two lectures on the Mosaic account of the Creation, in which he followed the early historical treatment, and placed the creation of man at 4000 B.C. Mr. Elvins undertook to disprove Professor Hirschfelder's views from geological evidence as to the antiquity of man. There were six letters from Mr. Elvins and two from Professor Hirschfelder. Mr. Elvins's arguments were stated in the straightforward and simple manner of one who is anxious to exhibit the truth and to clear away any difficulties which may exist. He certainly had the better of the argument. I think he rather enjoyed a newspaper discussion of a scientific subject and he had many apt and neatly turned expressions. I might quote the following sentences from one of these letters:

I am sorry to see some expressions which seem quite uncalled for, and to notice a spirit of bitterness towards myself showing occasionally. This is not needed in honest discussion: those who seek truth can afford to treat each other with kindness.

The Professor would wish your readers to think that I am dreaming also. I assure them, on the other hand, that I speak only the words of truth and soberness.

The Professor evidently does not regard the proof of man's antiquity which I have advanced as decisive; evidence of a different kind is at hand, equally important and far more interesting; let him "have patience and I will pay him all."

It was a great pleasure to him to meet any one who was devoted to the study of science, and he would discourse on his favorite geological or astronomical observations and theories at any length. In one of his letters he says: "I regard every student of nature as my personal friend."

I think, however, Mr. Elvins's connection with the discovery of Jupiter's fifth satellite is the most interesting episode in his scientific life. In one of his letters on the "Origin of the Solar System", dated January 4, 1873, he says:

Jupiter is far removed from the sun, when compared with the earth, and if our theory be correct, we should find him lighter, hotter, and pos

sessing a more dense and extensive atmosphere than the inner planets. Now, this is just what we find to be the fact in his case...... I have often watched the deeply shaded disc of Jupiter, his bright and dark belts, indicating a very extensive atmosphere, his rapid rotation and spheroidal figure giving the planet an oval shape, all seeming to indicate that the time is approaching when Jupiter will throw off its equatorial belt, and become, like Saturn, a ringed world.

The Great Red Spot was discovered in 1878, and it was studied assiduously by Mr. Elvins. At the meeting of the Astronomical and Physical Society on March 10, 1891, he read a paper on the Great Red Spot of Jupiter, of which the following is the printed summary12:

Mr. Elvins alluded to its appearance as a conspicuous object about ten years ago, and laid on the table drawings made by him at that time. The swift movement of the spot across the disc showed strikingly the rapid rate of the planet's rotation. The dark belt between the spot and the equator seemed to be driven from the spot by some repulsive force. Observation showed that white spots on the belts cross the disc in somewhat less time than the red spot does; the same is true of the belts themselves. Mr. Elvins suspects that the matter composing the red spot is above the atmosphere of Jupiter, and detached from it; if so, it would come under the operation of Kepler's laws, and would revolve slower than the planet rotates. He suggested the possibility of this being the first state of the existence of a satellite as yet but slightly condensed-a new satellite, in fact, in which case it would pass outside of the planet's disc; but evidence of this he had not been able to perceive. The spot ought to cast a shadow in transit. He thought the spot should be carefully observed for the purpose of ascertaining whether it can be detected beyond the disc, and of catching the shadow, if one exists.

At the meeting of the Society on October 4, 1892, Mr. Elvins made the following statement13:

In the Transactions of this Society for the year 1891, there was published an abstract of a paper of mine upon the Great Red Spot on Jupiter. In the course of that paper, I expressed the opinion that the planet is continually throwing off matter, which, by mutual attraction, forms solid masses, and I suggested that the Red Spot might be a mass of gaseous and "Transactions of the Astronomical and Physical Society of Toronto for 1891, p. 4.

Transactions of A. and P. Society for 1892, p. 67.