April 14, 1870] 
NATURE 
607 
The Solar Prominences 
Ir may interest some of your readers to hear that the bright 
lines of the hydrogen ‘‘flames” extending beyond the sun’s 
disc can be seen with much less instrumental aid than has hitherto 
been considered indispensable. I have succeeded in seeing them 
quite unmistakably by the following very simple means. I fixed 
one of Mr. Browning’s direct vision spectroscopes (having seven 
prisms) on a board which also carried a two-inch object-glass be- 
longing to a good field telescope. I mounted the instrument 
thus arranged (shall I say as an altazimuth) on the back of an 
ordinary bed-room mirror, and directed it at the sun. The slit 
was set so as nicely to divide the D line, and a blue glass was 
generally interposed in front of the slit to sift the light. As the 
image of the sun traversed the slit at intervals, the flames appeared 
as bright prolongations of the F line extending beyond the sun’s 
limb. It was also clearly seen at times that these prolongations 
were narrower than the F line and were not in the centre of it, 
also that they were frequently detached from the sun’s limb, and 
sometimes they were not straight : appearances depending as is 
generally supposed on the velocity and pressure of the gas in the 
flame. The flames were also readily seen in the C line. In ob- 
serving the solar spectrum I have found coloured glasses in front 
of the slit very useful to shut out as much as possible of the light 
from the parts of the spectrum not under observation. By using 
the spectroscope without its slit and collimating lens, and direct- 
ing it towards the great nebula in Orion, it shows close together 
three bright images of the nebula exhibited on a continuous spec- 
trum. 
Streatham Hill, April 8. ERNEST CARPMAEL 
Modern Geometry and the University of London 
THE letter entitled ‘‘ Euclid as a Text-book,” which appeared 
in last week’s NATURE, seems to me to call for immediate reply. 
Many students about to present themselves for examination at 
the University of London and other places during the next year 
have been told by their tutors that a thorough and accurate 
knowledge of geometry would be better appreciated than the 
power to make verbal transcriptions of Euclid ; and the letter 
referred to is calculated to shake the confidence of such students 
in the method they have been advised to pursue, and to produce 
a feeling of uncertainty as to the way in which demonstrations 
differing from Euclid’s will be received by the examiners. But 
I think that an inspection of the calendars will re-assure them, 
and show that they have no cause to fear the result of examina- 
tion, especially when the University of London is the examining 
body. 
The papers consist of certain propositions common to Euclid 
and modern text-books, and a number of problems readily solved 
by a student of modern geometry, but almost impossible to one 
who has simply committed to memory Euclid’s text. My own 
strong conviction is, that the latter would find some difficulty in 
passing the recent examinations. The questions given fall strictly 
within the University programme, and treat of important pro- 
perties of geometrical figures which no student possessing a 
knowledge of approved modern methods could possibly be 
ignorant of, The ‘alternative’ or modern side has been care- 
fully kept in view and placed on a footing of equality with the 
ancient system. 
During the year 1869 eight of my pupils who had zo? read 
Euclid were candidates for matriculation ; all passed, and none 
were placed lower than the first class ; so that I cannot see the 
advisability of boys returning to Euclid ‘‘in order that their pro- 
spect of good places may be enhanced.” 
Mr. Tucker apparently desires a series of questions which 
could only be answered on modern principles. This would amount 
to a system of protection, and could not fail to be objectionable. 
The student of the New Geometry has, in fact, a great advan- 
tage. To the learner of Euclid a fact clothed in terms slightly 
varying from Euclid’s is often new and startling, but to the 
modern student who learns every proposition in its most general 
form, and assimilates the idea apart from the external or verbal 
form in which it may accidentally be presented, it is already 
familiar and trite. The statement that a change in the London 
syllabus has been or will be made ‘“‘as a sop to Cerberus,” 
will strike many as singularly infelicitous and ungenerous. The 
Senate of the University does not say one thing and mean 
another ; it has always shown unflinching courage in the reform 
of English methods of education, legislating as an_ initiator 
rather than as a follower. The tendency of the University 
throughout its existence has been to discourage cramming in 
every shape and form, in the teeth of numerous difficulties and 
influences to which the term ‘‘ obstructive” rightly applies rather 
than to the University itself. It is to be regretted that a letter 
dating from University College School should show so little 
confidence in the intrinsic superiority of modern methods, and 
still more that it should impeach the integrity of men who have 
not so deserved. 
Brixton, March 28 RICHARD WORMELL 
DEATH OF PROFESSOR MAGNUS 
@©* the 4th of April, 1870, at a quarter-past ro p.m., 
died peacefully, after a long illness, Dr. Gustav 
Magnus, Professor of Physics, and Director of the Physical 
Cabinet in the University of Berlin. He was an experi- 
mental philosopher of great and varied excellence, 
executing his work with the choicest apparatus and 
with the most conscientious care. His numerous labours 
are known to all students of physics, and they are such 
as to secure for him an enduring fame. On the 28th 
of April, 1851, I first saw Professor Magnus on his own 
doorstep in Berlin. His aspect won my immediate 
regard, which was strengthened to affection by our sub- 
sequent intercourse. He gave me a working place in his 
laboratory, and it was there I carried out the investigation 
on Diamagnetism and Magne-crystallic Action, which is 
published in the Phzlosophical Magazine for Sept. 1851. 
In 1853 I was again in Berlin, and found under his roof 
the same ready help and sympathy. Professor Hirst and 
myself paid him a visit last summer ; and he afterwards 
attended the Exeter Meeting of the British Association, 
where his frank, genial, and gentlemanly demeanour were 
conspicuous to all. Over and above his direct contribu- 
tions to Science, Prof. Magnus exercised a powerful in- 
direct influence, through the kindly aid and countenance 
which he lent to young inquirers. When I bade him 
good-bye in 1851 his last words to me were, “If you 
should meet any really able young fellow, willing to work, 
and to whom such assistance as I can render would be 
valuable, send him to me.” There are many such, now 
no longer young, who, like myself, will mingle a grateful 
memory of his goodness with their grief for his loss. 
Royal Institution, 11th April JOHN TYNDALL 
THE SOURCES OF THE NILE* 
“|e main point of interest in the latest travels of 
Livingstone, and that which gives to them a dis- 
tinctive importance over the great accomplishments of 
his former journeys, is, that in these, Livingstone has 
undoubtedly visited and beheld the long-sought-for 
sources of the Nile. It is true that there still remains 
considerable doubt as to which of the basins that he has 
explored will ultimately be acknowledged as the cradle 
of the Nile, but this at least is certain, that the real 
head streams have been seen by him, and the vexed 
question has by these explorations resolved itself into a 
choice between two or perhaps three streams. Livingstone 
himself has apparently no bias in favour of one or other, 
so that the discussion is a perfectly open one. The three 
rival head streams are, first, the feeders of Lake Liemba, 
and second the Chambeze River and its lake chain, both 
of which rise near the eastern edge of the great longitu- 
dinal plateau of the side of Africa next the Indian Ocean ; 
the third is the source recently claimed for the Nile by 
* An abstract of part of a paper read before the Royal Society of Edin- 
burgh, March azst. 
