
- Yaly 27, 1871] 
chromatic light, and that light of the very colour composing the | 
various layers, each layer being, as [ have shown, so much 


e 
brighter than the outer ones that its light predominates over them, 
Ts it too much to suggest to those who may be anxious to attempt 
to elucidate this subject, that probably if they would consider 
all the conditions of the problem presented by that great screen, 
the moon, allowing each of these layers by turn to throw its light 
earthwards, the inequalities of the edge of the globular moon 
allowing here light to pass from a richer region, here stopping 
light from even the dimmer ones, they would be able to explain 
the rays, their colours, variations, apparent twistings, aud change 
of side? Ido not hesitate to ask this question, because it is a 
difficult one to answer, since the whole question is one of enor- 
mous difficulty. But difficult though it be, I trust I have shown 
you that we are on the right track, and that in spite of our bad | 
weather, the observations made by the English and American 
Government Eclipse Expedition of 1870 have largely increased 
our knowledge. 
With increase of knowledge generally comes a necessity for 
changing the nomenclature belonging to a time when it was im- 
perfect. 
form no exception to this rule. A few years ago our science was 
satisfied with the terms prominences, sierra, aud corona, to re- 
present the phenomena I have brought before you, the nature of 
both being absolutely unknown, as is indicated by the fact that | 
the term svrva was employed, and aptly so, when it was imagined 
the prominences might be solar mountains! We now know 
many of the consti uent materials of the-e strange things; we 
know that we are dealing with the exterior portion of the solar 
atmosphere, and a large knowledge of solar meteorology is al- 
ready acquired, which shows us the whole mechanism of these 
prominences. But we also know that part of the corona is 
not at the sun at all. Hence the terms /eicosphere and halo have 
been suggested 10 designate in the one case the regions where the 
general radiation, owing to a reduced pressure and temperature, 
is no longer subordinate to the selective radiation, and in the 
other, that part of the corona which is non-solar. Neither of 
these terms is apt, nor is either necessary. All purposes will be 
served if the term corona be retained as a name for the exterior 
region, including the rays, rifts, and the like, about which doubt 
still exists, though it is now proved that some part is oz-solar, 
while tor the undoubted solar portion the term Chromosphere— 
the biight-line region—as it was defined in this theatre now two 
years ago, exactly expresses its characteristic features, and 
differenuates it fr. m the photosphere and the associated portion 
of the solar atmosphere. 
Here my discourse would end, if it were not incumbent on me 
to state how graceful 1 feel to Her Majesty's Government for 
giving us the opportunity of going to the eclipse; to place on 
record the pleasure we all felt in being so closely associated in 
our work with the distinguished American astronomers who from 
fir-tto last aided us greatly ; and to express our great gratiiude 
to all sorts of new fnends whom we found wherever we went, 
and who welcomed us as if they had known us from our child- 
hood, J. Norman Lockyer 


ON THE DISTRIBUTION OF TEMPERATUKE 
IN THE NORTH ATLANTIC 
AT the request of the Council of the Scottish Meteorological 
Society, I beg to bring before you a sketch of the more 
recent results of investigations into the causes of the abnormal 
climate of the surface of a great portion of the North Ailantic 
Ocean, and of the lands which form its north-eastern borders ; 
and especially the results of the deep-sea explonny expeditions 
of the last three years, in which | have takena part, so sar as they 
bear upon this point. 
In arecent valuable report on the Gulf Stream in the ‘‘ Geo- 
graphische Mittheilungen,” of last year, Dr. Petermann severely 
and, | think, too justly, reflected upon us students of ocean tempe- 
ratures for giving ourselves up to wild and gratuitous speculation. 
I wish, if possible, on the present occasion, to avoid all risk of 
such impeachment, by limiting our inquiry rigidly for the few 
minu’es I have at my disposal to the present condition of our 
knowledge of facts, and to such deductiuns from these as may be 
fairly considered proved. 
* Acdress deiivered to the Meteorological Society of Scotland at the 
_ General Meeting of the Society, July 5. 
The researches to which I have drawn your attention | 

NATURE 

251 

Let us then first inquire for a moment what the phenomena 
are which we are called upon to correlate and to explain. There 
is no dispute about these facts, and a glance at the chart will 
at once recall them to your recollection. In the first place, 
the lines of equal mean annual temperature, instead of showing 
any tendency to coincide with the parallels of latitude, run up 
into the North Atlantic and into the North Sea, in the form 
ofa series of long loops, ‘This diversionof the isothermal lines from 
their normal direction is admittedly caused by surface ocean- 
currents conveying the warm tropical water towards the polar 
regions, whence there is a constant counter-flow of cold water 
beneath to supply its place. This phenomenon is not confined 
to the North Atlantic. A corresponding series of loops, though 
not so well defined, passes southwards along the east coast of 
South America, and a very marked series occupies the north- 
eastern angle of the Pacific, offthe Aleutian Islands and the coast 
of California, ‘The temperature of the land is not affected di- 
rectly by the temperature of the sea in its immediate neighbour- 
hood, but by the temperature of the prevailing wind, which is 
determined by that of the sea. Setting aside the still more im- 
portant point of the equalisation of summer and winter tempera- 
ture, the mean annual temperature of Bergen, lat. 60° 24’ N., sub- 
ject to the ameliorating influence of the south-west wind blowing 
over the temperate water of the North Atlantic, is 6°7° C, while 
that of Tobolsk, lat. 58° 13’, is —2°4° C. 
But the temperature of the North Atlantic is not only raised 
greatly above that of places on the same parallel of latitude 
having a continental climate by this in'erchange of tropical and 
polar water, but it is greatly higher than that of places appa- 
rently similarly circumstanced as to a general interchange of 
water in the Southern Hemisphere. Tnus, the mean annual 
temperature of the Faroe Islands, lat. 62° 2'N.is71° C. nearly 
equal to that o! the Falkland Islauds, lat. 52°S., whichis 8 2°C., 
and the temperature of Dublin, lat. 53° 21’ N., is 9°6° C., while 
that of Port Famine, lat. 53° 8S, is 5°3°C. Again the high 
temperature of the North Atlantic is no: equally distributed, but 
is very marked in its special determination to the nortl.-east 
coasts. Thus, the mean annual temperature of Halifax, lat. 
44° 39’, is 62" C., while that of Dublin, lat. 53° 21’ isg6C., 
and the temperature of Boston (Mass.) lat. 42° 21’ is exacily the 
same as that of Dublin. 
We thus arrive at the well-known general result, that the tem- 
perature of the sea bathing the north-east shores of the North 
Avantic is greatly raised above i's normal point by currents in- 
volving an interchange of tropical and polar water ; and that the 
lands bordering onthe Neurth Atlantic participate in this ameliora- 
tion of climate by the heat imparted by the water to their prevail- 
ing winds. 
We shall now examine this distribution of ocean temperature 
a little more minutely. During the last many years a prodigious 
amount of data have been accumulating with re erence to the 
detailed distribution of heat on the surface o! the No th Atlantic 
besin, and last year M. Petermann, of Gotha. published in his 
“ Geographische Mittheilungen ” a series of invaluable temperature 
charts embodying the resuits of the reduction of upwards of 
100,000 observations derived mainly from the following sources :— 
I-t. Fromthe wind and currentcharts of Lieut. Maury, em- 
b: dying about 30,000 distinct temperature observations. 
2nd. From 50,000 observations made by Dutch sea captains 
and published by the Government of the Netherlands. 
3rd. From the journal of the Cunard steamers between Liver- 
pool and New York, and of the steamers of the Montreal 
Company between Glasgow and Felleisle. 
4h. From the data collected by our excellent secretary, Mr. 
Buchan, with regard to the temperature of the coast of 
Scoiland. 
sth. From the publications of the Norwegian Institute on sea 
temperatures between Norway, Scotland, and Iceland. 
6th. From the data furnished by the Dani-h Rear-admiral 
Irminger on sea temperatures between Denmark and the Danish 
settlements in Greenland. 
7th. Froni the observations made by Lord Dufferin on board 
his yacht /oam between Scotland, Iceland, Spitzbergen, and 
Norway. 
And finally from the recent observations collected by the Eng- 
Jish. German, Swedish, ani Russian expeditions to the Arctic 
Regions and towards the North Pole. 
Dr. Petermonn has devo ed the special attention of a great part 
of his life to this question, and the accuracy ot his results in every 
deiail is beyond the shadow of adoubt. Every curve of equal 
temperature, whether for the summer, for the winter, or for the 
