Fan. 30, 1873) 
tric sparks through a tube containing hydrogen at the 
pressure of one atmosphere, we shall see that the colour 
of the incandescent gas is a bright carmine red, the spec- 
- trum of which can easily be cbserved by placing the 
spark tube in front of the slit of one of the spectroscopes 
before described. This arrangement is one that is in 
daily use in many of our laboratories, and it must be 
borne in mind as being the modus operandi by which a 
"great deal of the work has been done to which I shall 
have to allude shortly. If again we take a tube which 
contains hydrogen that has been extremely rarefied, 
and pass a series of electric sparks through it, instead of 
having the brilliant red colour, we shall have a palegreenish 
spark, quite different from the former. This great difference 
is due to the difference in the pressures of the hydrogen 
of the two cases. 
The two spectra are equally distinct, the red light shows 
three splendid lines, one in the red, another in the bluish 
green, and the third in the violet, together with a con- 
siderable amount of continuous spectrum, whilst almost 
the only spectrum which can be obtained in the second 
case, is a single green line in the same position as the 
former green line spoken of. There is also this difference 
which will be observed, that the green line obtained from 
the tube at the atmospheric pressure is very broad and 
indistinct at the edges; and that the line as seen from 
the almost vacuous tube is very thin, comparatively speak- 
ing, and perfectly sharp and well defined. If we were to 
take another tube, with a pressure somewhere between 
the two already mentioned, it would be seen that this 
green line was not so wide and woolly as in the tube 
at one atmosphere, and yet not so sharp and well 
defined as in the almost vacuous tube. Thus it will be 
seen that this widening out of the line is due to the 
. difference of pressure. 
J. NORMAN LOCKYER 
(To be continued.) 
NOTES 
Our readers will be sorry, though not surprised, to hear that 
the venerable Professor Sedgwick died at Trinity College, 
Cambridge, on the morning of the 27th instant, aged 87 years. 
He was fifth wrangler in Trinity in 1808, and was elected to a 
fellowship in 1810, His contributions to science were very 
numerous, and are mainly to be found in the Transactions of 
various learned societies. 
THE Vice-Chancellor of Cambridge University has given 
notice that the election of a Woodwardian Professor of Geology, 
in the place of Dr. Sedgwick, will be held in the Senate House 
on Thursday, February 20, at 1 P.M. The Vice-Chancellor and 
Proctors will receive the votes from I to 2.30, when the election 
will be declared. The stipend attached to the professorship is 
soo/7, per annum. 
WE are very glad indeed to hear that renewed and better 
organised efforts are likely to be made to induce Government to 
undertake the expense of an Arctic expedition. We have good 
reason to believe that Sir Henry Rawlinson will address a letter 
to the President of the Royal Society urging the importance of 
that body taking a lead in the advocacy of such an expedition, 
This is as it should be, and we have no doubt if the matter is 
gone about in a thoroughly well considered manner, a second re- 
buff will not be experienced. Meanwhile we are glad to learn 
from an obliging correspondent that Mr. Leigh Smith will pro- 
ceed on his third voyage of Arctic discovery in the spring. He 
has a fine strong steamer, the Diana, admirably adapted for the 
purpose ; and will undoubtedly achieve all that can be done in 
the way of discovery in the Spitzbergen seas, during the season 
of 1873. For Mr. Smith is a good observer and explorer, and 
ig now becoming a veteran Arctic voyager. In 1871 he made 
NATURE 
249 
the most remarkable voyage in that direction since 1707, disco- 
vering a large extent of coast line both on the north and south 
sides of North East Land. He also attained the highest lati- 
tude that has been reached in a ship, except by Scoresby and the 
Swedes. In 1872 he went out again, and though the unfavour- 
able state of the ice prevented him from doing much, he suc- 
ceeded in taking a very important series of observations of sea- 
temperatures at various depths. In 1873 he will again, with — 
better means and in a steamer instead of a sailing vessel, make 
an attempt to explore the unknown lands east of Spitzbergen, 
and to attain the highest latitude that skill and perseverance will 
enable him to reach. 
THE Senior Wrangler at Cambridge this year is Mr. Thomas 
Olver Harding, eldest son of the Rev. Thomas Harding, Wes- 
leyan minister of Whitehaven. Mr, Harding, in January, 1866, 
gained the first exhibition at the matriculation examination of 
the London University, and the Gilchrist Scholarship at Uni- 
versity Hall. In 1867 he gained the Andrews Scholarship in 
mathematics at University College. In 1868 he proceeded to 
the degree of B.A., in the University of London; and in 1869 
and 1871 he passed the first and second examinations for the 
degree of B.Sc., gaining the exhibition in mathematics at each. 
Last year he was elected fellow of University College. In 
1869 he entered Trinity as senior minor scholar in mathematics, 
and was elected foundation scholar in 1871. Mr. Harding 
has just completed his twenty-third year. His private tutor was 
Mr, Routh; his college tutor the Rev. E. W. Blore. .The 
Second Wrangler, Mr, Edward John Nanson, was educated at 
the Grammar Schools of Penrith and Ripon. In 1869 he ob- 
tained a Minor Scholarship at Trinity College. In July 1869, 
he commenced reading with Mr. Routh, of St. Peter’s College. 
In 1870 he obtained a Foundation Scholarship. He was Prize- 
man, and placed in the first class at each of the annual College 
Examinations. His college tutor was Mr. Blore. 
AN alteration has been made in Prof. Tyndall’s arrangements. 
We are now enabled to state that he will leave America on the 
5th of next month in the Cuda. 
WE are glad to see from the account of the annual meeting of 
the Anthropological Institute officially forwarded to us, that Prof. 
Busk has been elected President, and along with him the follow- 
ing strong Council :—Vice-Presidents—John Beddoe, M.D. ; 
J. Barnard Davis, M.D., F.R.S. ; John Evans, F.R.S. ; Col. 
A. Lane Fox, F.S.A.; Prof. Huxley, F.R.S.; Sir John 
Lubbock, Bt., F.R.S.  Director—E. W. Brabrook, F.S.A. 
Treasurer—J. W. Flower, F.G.S. Council—H. G. Bohn, 
F.R.G.S.; Capt. R. F. Burton; A, Campbell, M.D.; Hyde 
Clark ; W. Boyd Dawkins, F.R.S. ; Prof. P.M. Duncan,'F.R.S.; 
Robert Dunn, F.R.C.S. ; David Forbes, F.R.S. ; A. W. Franks ; 
Francis Galton, F.R.S.; C. R. Markham, C.B. ; Capt. Sher. 
Osborn, C.B., R.N.; Capt. Bedford Pim, R.N.; F. G. H. 
Price, F.G.S. ; J. E. Price; F. W. Rudler, F.G.S.; C. R. Des 
Ruffiéres, F.R.S.L. ; W. Spottiswoode, V.P.R.S. ; E. Burnet 
Tylor, F.R.S. ; A. R. Wallace, F’.L.S. 
A work of considerable importance, a geological map of 
Australia and Tasmania, has been recently commenced by Mr. R. 
Brough Smyth, secretary to the Mining department of the 
Australian Government, which, when finished, will be of value 
not only to the colony, but to the whole scientific world. As 
the Minister of Mines has cordially approved of the work, it is 
intended to communicate with the Governments of the various 
colonies, forwarding a draft of the map after it has been partially 
completed from the sources at hand, and a scale showing the 
colours of the various rock formations, with a request that they 
will as far as possible fill in the blanks from the records of the 
departments in the respective colonies. By this means it is 
anticipated that much zeliable information will be obtained, as 
