198 
NATURE 
| Fuly 13, 1871 

(or some equivalent arrangement) directed to the sun’s 
centre, to record any changes which take place in the 
spectrum from, say, half an:hour before to half an hour 
after totality, and during totality, zen entendu. The re- 
lative darkness or brightness of the lines should be re- 
corded every ten seconds. 
“This spectroscope should have moderate dispersion, 
large object-glasses for collimator and telescope, and with 
focal length such that two or three degrees round the sun 
should be taken in (é,e., 1° or 13° from the sun’s centre), 
and a large field. . . . 
“To come to the details of the expedition to Ceylon ; 
I am of opinion that it need not exceed the following 
numbers, as my Sicilian experience has taught me that 
we may depend upon much valuable help from the officers 
at the place of observation :— 
“t Telescope-Spectroscopic observer ; 2 assis- 
tants. 
“t Photographer ; 2 assistants. This duty per- 
haps may be entrusted to skilled Sappers. 
“1 Spectroscopic observer ; I assistant, or 8 in 
* “Among general observations, I would point out as 
being of extreme importance : 
“a. Rays before, during, and after totality—their 
length, direction, and colour. 
“8, Colours of the various layers of chromosphere, 
and of clouds and landscape. The order of these 
colours is of great importance. 
“y, Dark rays or rifts; whether they change, 
and whether they extend to the dark moon, or stop 
short above the denser layers of the chromosphere. 
“6. The colours of the corona between bright or 
dark rays. 
“e, All changes in corona, 
“€ Comparative brightness of rays and chromo- 
sphere and outer corona. . ... . 
“Tn the above letter the nomenclature employed is the 
one I suggested in a recent lecture at the Royal Institu- 
tion, namely : 
“ Corona, embracing the whole compound pheno- 
menon outside the prominences (including rays and 
streamers), part of which is undoubtedly non-solar. 
“ Chromosphere, embracing the whole of the solar 
portion of corona, and all bright line regions out- 
side the photosphere.” 
It is scarcely necessary to point out th. ©“ above 
deals with possibilities, rather than wita-a. _ oilities. 
We are convinced that a much larger party would do good 
work in Ceylon, but our scientific leaders are right in 
asking what our Government cannot refuse; and, more- 
over, we may hope that the magnificent stations in India 
on the Neilgherries, at considerable elevations, will be 
strongly garrisoned, as they can well be by the eminent 
observers now in India. 
We trust that these efforts to procure fresh observations 
will meet with the largest measure of success, for certainly 
the question of the Sun’s Corona is the scientific question 
of theday. Once settle what isthe real nature of the sun’s 
surroundings, and the path of work is open for the more 
distant stars. Solong as our knowledge of the sun is 
clouded by contending hypotheses, we cannot hope for 
real progress. 
For our part we do not doubt that the Government will 
act as admirably as they did last year inthe same branch 
of research when the requirements of Science are properly 
laid before them ; and if the elements are equally kind, 
we may hope for a large increase of our knowledge, 

TYNDALL’S “HOURS OF EXERCISE IN 
THE ALPS” 
Hours of Exercise in the Alps. By John Tyndall, LL.D., 
F.R.S. (London: Longmans.) 
HIS volume is a collection of short articles which 
have already seen the light in various publications, 
and are here thrown together, as the author says, “ partly 
to preserve to myself the memory of strong and joyous 
hours, and partly for the pleasure of those who find exhi- 
laration in descriptions associated with mountain life.” 
Accordingly we find in it accounts of exciting scrambles, 
such as the Lawinenthor and the Old Weissthor, the first 
ascent of the Weisshorn, and the various assaults upon the 
Matterhorn, crowned at last with success. Of sadder 
interest are the story of the death of Benner, the pro- 
fessor’s faithful guide, upon the Haut de Cry, contributed 
by one of the survivors ; notices of the accidents on the 
Col de Géant and on the Matterhorn ; and, hardly less in 
interest though with happier ending, the rescue of a porter 
from the jaws of a crevasse on the great Aletsch Glacier, 
and the author’s own hairbreadth escape on the Piz 
Morteratsch. All these are described with his usual graphic 
power and intense appreciation of natural scenery; 
sometimes in the philosophic vein, when a glass of whisky 
gives “a flash of energy,” and even a ham sandwich can 
only be regarded as a conditioned form of potential mus- 
cular force ; or sometimes in the more jubilant mood, when 
we are shown the grave professor “delighting to roll 
himself in a bubbling pool in some mountain stream, and 
afterwards dance himself dry in the sunshine.” 
Together with these sunny memories of alps and cascades, 
snow-fields and glaciers, there are some chapters of a more 
distinct scientific import, to which, as most germane to 
the pages of NATURE, we shall confine our notice. The 
first of these—the twentieth in the volume—is on Alpine 
Sculpture. The professor, we need hardly say, is a strong 
“Erosionist,” attributing the valleys to the sculpturing 
influences of water, frost, and ice, as opposed to those who 
regard them as the result of fissures in the earth’s crust 
produced by strains during its upheaval. His summary 
of the evidence for “sculpture v. fracture” strikes us as 
particularly good, and, as it happens, we can bear testi- 
mony from personal experience to the accuracy of the 
facts cited. He shows that by a simple geometric calcu- 
lation, the width of the fissures produced by the upheaval 
of a hundred miles of the earth’s crust to a maximum 
height of four miles would bear a very small ratio to the 
width of the existing valleys; therefore that the most 
which can be claimed for fissures is that they have guided 
the action of meteoric forces, have, as it were, drawn the 
rough sketch on the stone which has directed the picks of 
Nature’s quarrymen, and guided the chisels of her sculp- 
tors. He points out that in the most fissure-like of gorges, 
such as those of the Via Mala or Pfaffers, characteristic 
water-marks are visible from top to bottom. His descrip- 
tion of the latter may be taken as a summary of the evi- 
dence in these and many other cases which he has quoted. 
“Here the traveller passes along the side of the chasm, 
midway between top and bottom. Whichever way he 
looks, backwards or forwards, upwards or downwards, 
towards the sky or towards the river, he meets everywhere 
the irresistible and impressive evidence that this wonder- 
ful fissure has been sawn through the mountain by the 

