230 



NA TURE 



\July 5) 1883 



America, which retain several rather generalised mam- 

 malian characters, and are related to some of the earliest 

 known European Miocene forms, are both to the present 

 day exclusively fluviatile, being found in the rivers they 

 inhabit almost up to their very sources, more than a 

 thousand miles from the sea. May this not point to the 

 freshwater origin of the whole group, and thus account 

 for their otherwise inexplicable absence from the Cre- 

 taceous seas ? 



We may conclude by picturing to ourselves some primi- 

 tive generalised, marsh-haunting animals with scanty 

 covering of hair like the modern hippopotamus, but with 

 broad, swimming tails and short limbs, omnivorous in their 

 mode of feeding, probably combining water plants with 

 mussels, worms, and freshwater crustaceans, gradually 

 becoming more and more adapted to fill the void place 

 ready for them on the aquatic side of the borderland on 

 which they dwelt, and so by degrees being modified into 

 dolphin-like creatures inhabiting lakes and rivers, and 

 ultimately finding their way into the ocean. Here 

 the disappearance of the huge Enaliosaurians, the 

 Iclitliyosauri and Plesiosauri, which formerly played 

 the part the Cetacea do now, had left them ample scope. 

 Favoured by various conditions of temperature and 

 climate, wealth of food supply, almost complete immunity 

 from deadly enemies, and illimitable expanses in which to 

 roam, they have undergone the various modifications to 

 which the Cetacean type has now arrived, and gradually 

 attained that colossal magnitude which we have seen was 

 not always an attribute of the animals of this group. 



Please to recollect, however, that this is a mere specu- 

 lation, which may or may not be confirmed by subsequent 

 palaeontological discovery. Such speculations are, I 

 trust, not without their use and interest, especially when 

 it is distinctly understood that they are offered only as 

 speculations and not as demonstrated tacts. 



THE AMERICAN OBSERVATIONS OF THE 

 ECLIPSE 



NEWS of the American observations of the last eclipse 

 has now arrived, and although details are yet want- 

 ing, enough information has been sent to show us that, 

 as was to be expected, the American observers have left 

 their mark upon the work. The telegram given below 

 has been forwarded to me by the editors of Science, and 

 is one transmitted by Prof. Holden to Prof. Young on the 

 arrival of the former at San Francisco : — 



" San Francisco, Cal., June 1 1 

 "American Eclipse Expedition arrived at St. Francisco 

 June 11. Holden reports no Vulcan as bright as 5i mag- 

 nitude. Hasting' s observations prove the corona to be 

 largely a phenomenon of diffraction by the great change 

 in lengh of 1474 line on east and west sides of sun. No 

 black lines in corona spectrum but D. Full observations 

 with grating spectroscopes, prismatic telescope, and in- 

 tegrating spectroscope, by Rockwell, Upton, and Brown. 

 Contacts by Preston. English and French parties suc- 

 cessful. (Signed) E. S. Holden " 



It will be seen from the above that the spectroscopic 

 attack was a very strong one, and although the telegram 

 gives only the results of the work of Prof. Hastings, these 

 are of unusual interest. I propose, therefore, to devote 

 attention to them in the present notice. It will, how- 

 ever, be well to anticipate my remarks by a prefatory 

 notice of the eclipse work on which it throws light. For 

 this purpose I can scarcely do better than give the fol- 

 lowing extract from an article which appeared in the 

 Times on Monday last : — 



''It was only really in the eclipse of 1869 that we 

 began to know anything about the corona, and it was 

 only in the eclipse of 1S70 that we began to appreciate 

 what a very difficult problem was presented to us by that 



phenomenon. The then Astronomer- Royal and Prof. 

 Maedler, to cite some among the eminent authorities 

 writing after the eclipse of i860, had come to the conclu- 

 sion that the corona was mainly a non solar phenomenon. 

 That pari of it, however, was undoubtedly solar was 

 admitted by all, for the reason that it was seen before 

 and after totality. In the eclipse of 1870 the idea that 

 part of it was really non-solar was enormously strength- 

 ened by a comparison of observations made by different 

 astronomers. Its shape seemed to change as the moon 

 swept over it, and this obviously, if it were true, implied 

 some action of the moon's edge and reflection by some- 

 thing between the observer and the moon. In 1871, 

 when the Government of India and the British Associa- 

 tion took steps to have the corona photographed at the 

 same time that it was carefully observed by the naked 

 eye, the strange fact was first clearly indicated that the 

 corona seen by the eye was a perfectly different thing to 

 that recorded on the photographic plates. The explana- 

 tion given at the time was that the coronal light was 

 much more actinic than ordinary solar light of the same 

 visible intensity, so that in the eye and on the photo- 

 graphic plate two different images were built up by 

 different qualities of light proceeding from different 

 sources. Hence the view was distinctly enunciated that 

 the corona seen during eclipses was a dual phenomenon, 

 partly solar, partly non-solar in its origin, the true solar 

 corona being filamentous with variously-curved streamers, 

 the visible corona being non-filamentous and consisting 

 mainly of radial lines and rifts, extending to different 

 distances from the edge of the moon " 



This slight sketch may now be expanded by the follow- 

 ing details. Thus, for instance, in March, 1870, Prof. 

 Young, discussing the then current views of the corona, 

 wrote :—" It is not impossible that the so-called corona 

 may be complex, some portion of its radiance may per- 

 haps originate in our own atmosphere, though I do not 

 yet find myself able to agree with the conclusion of Dr. 

 Gould and Mr. Lockyer in this respect, and am strongly 

 disposed to believe that the whole phenomenon is purely 

 solar." 



With reference to the eclipse of 1870 I wrote: — "At 

 the commencement and end of totality, when the moon 

 unequally covered the sun, the photographs have recorded 

 an excess of light on the corona on the side where the 

 limbs occur nearest in contact. I am told that this effect 

 in one of Lord Lindsay's photographs is very striking ; it 

 is certainly so in one of Mr. Brothers'. In the drawings 

 we have a slightly different effect. At the commencement 



of totality, when the western or right-hand limbs were in 

 contact, we get (see figure) 1 ; at the end of totality the 

 appearance recorded was like 2 ; the picture at the 

 middle of totality compounding both these appearances, 

 and being roughly represented by 3. in which the rectan- 

 gular appearance comes out in its full strength." 



Let us pass on to the eclipse of 1871. This was my 

 description, written at the time, of what I saw :—" There, 

 rigid in the heavens, was what struck everybody as a 

 decoration, one that Emperors might fight for ; a thousand 

 times more brilliant even than the star of India,— where we 

 then were, — a picture of surpassing loveliness, and giving 

 one the idea of serenity among all the activity that was 

 going on below, shining with a sheen as of silver essence, 

 built up of rays almost symmetrically arranged round a 

 bright ring above and below, with a marked absence ot 



