Oct.\29, 1885 | 
NATURE 
631 
metres. The labour to attain even such accuracy is 
very great. The surprise is that at Upsala they did not 
adopt a photographic theodolite such as is now, we 
believe, in daily use at Kew. In the Kew “nepho- 
graphs,” as they are called, the telescope is replaced by 
a camera, and the observations do not involve half the 
labour of eye-observations. For instance, when the two 
nephographs are in a fixed position the manipulations are 
simplicity itself. One observer telephones to the other 
the cloud whose height it is desired to ascertain. By 
means of a very simple pointer both direct their cameras 
to the cloud, having inserted a dry plate in position. The 
lenses are closed by shutters, both of which can be opened 
and then closed with any desired rapidity by an electrical 
arrangement from one station. The exposures are thus 
made simultaneously, and the photograph must include 
every point in the cloud. The position of the cloud is 
fixed by crossed lines etched on a glass plate which is in 
contact with the dry plate, and which always occupies the 
same position, and from these cross lines, which are im- 
pressed on the two negatives, any desired pointis measured. 
The readings of the graduated circles of the nephoscope 
having been taken the height and distance of the cloud is 
readily calculated. It might be supposed that consider- 
able errors might be made even with this arrangement 
as the solid angular distance included is somewhere about 
55, and the objects within this are impressed on a plate less 
than six inches square. Asa matter of fact, such is not the 
case. Measurements of objects a couple of miles off, and 
at known distances from the observer, have been observed 
with an error of less than 1 per cent., a base of 250 yards 
having been used—an accuracy which is far greater than 
could be obtained by eye-observations when the object to 
be observed is uncertain in outline, and when there is no 
definitely fixed point to observe. It must not, however, 
be supposed that there are no difficulties in photographing 
clouds of every description. It requires, for instance, a 
keen judgment to hit off the exposure necessary to differ- 
entiate between the white clouds in the higher regions the 
pale blue sky against which they are projected. All such 
difficulties are to be overcome with practice. It is to be 
hoped that before long the Upsala Observatory will adopt 
such a plan as we have indicated, when the results they 
obtain will be even more valuable and be less laboriously 
attained than they are at present. 
The following table gives the height of the different 
characters of clouds at Upsala :— 
Stratus j ‘ 625 metres. 
Nimbus (lower) . : pitsicy yy 
» higher Diels) | 
\ top 1,690 
Cumulus and cumulo-stratus } base 1,307 
;, mean 1,498 
Lower alto-cumulus : : 1,988 
Higher ,, 5 : : 4,242 
Cirro-cumulus  . 6 : 55513 
Cirrus’. : 6,823 
The authors point out that, according to their observa- 
tions, apparently there are seven levels, each one occupied 
by a different species of cloud, viz. : 600, 1,100, 1,500, 
2,000, 42-4,600, 58-6,6co, and 80-8,600 metres ; and these 
levels agree with those deduced by M. Vettin of Berlin, 
who deduced them from a different mode of observation. 
There are several remarkable tables, some of which give the 
diurnal variation in the height of clouds, others the diurnal 
variation of the frequency of high clouds at Upsala during 
the summer, others again which discuss the question of 
the effect of the height of the barometer on the cloud 
masses. One of the most interesting sections of the 
memoir is that on the calculation of the velocity of wind 
at different heights from the movements of clouds, 
On the whole, the Observatory at Upsala is to be con- 
gratulated on the step it has taken in making systematic | 
observations of cloud heights and velocities. It isa matter 
of capital importance to meteorology that such should be 
undertaken in various localities, not only at or near the 
sea level, but also at as high altitudes as possible. Were 
the cloud levels, for instance, the same at all places, 
mountainous districts would be very much more cloud 
bound than we know is the case. Observations of clouds 
in the Alps show that the levels at which the different 
classes are to be found exceed the heights which are 
shown in the table above; and it remains to ascertain not 
only the effect of barometic pressure on the levels, but 
also the disturbing effect caused by the elevations in the 
land. Such observations might well be added to the 
observatory at Ben Nevis, and no doubt some enthusiastic 
meteorologist would be willing to spend a summer in the 
Alps to make observations at a still higher station. Until 
work such as this is undertaken the subject can only be 
partially discussed on scientific grounds. 
W. DE W. A. 
THE RECENT TOTAL ECLIPSE OF THE SUN 
E have received the communica- 
tions :— 
THE news that bad weather seriously interfered with 
the work of the Government Survey parties, sent to 
observe the eclipse of the 9th inst. from points on the 
centre line of totality, induces me to send you the 
accompanying incomplete sketch and hasty account by 
to-day’s mail :-— 
I observed the eclipse from Tahoraite, the present 
southern terminus of the Napier-Wellington Railway, a 
point well within the belt of totality, but some forty miles 
north of the centre line. 
I went, determined to concentrate my whole attention 
on the corona, and the corona alone—I did not even take 
my watch. My eclipse observations are therefore neces- 
sarily very incomplete. 
After a stormy night (alternate showers of rain and hail, 
with a bitterly cold wind), day-dawn brought a clear 
sky ; but a heavy bank of clouds far away to the south 
boded no good to observers in that direction. The cold 
was bitter, and fresh snow lay very low down on the 
neighbouring hills. 
The first contact occurred not long after sunrise, the 
atmosphere in the east being rather hazy, and the light 
pale (other observers say ruddy). At first the tempera- 
ture of the air seemed to rise steadily, but when the sun’s 
disk was a quarter obscured, it began to fall again, and 
as totality approached the cold became severe. 
When the occultation of the sun had reached three- 
quarters, the so-called “livid” character of the light 
became very marked, and about ten minutes before 
totality a curious and tremulous play of light on the 
ground—like dark ripples or moving “‘marblings,” if I 
may use the word, became apparent. 
In order to keep my eyes as sensitive as possible to the 
faint light of the corona when it should become visible, 
I only watched the sun (through a telescope) for a few 
minutes after first contact, I then averted my gaze, and 
fixed it persistently on the dark-green bush surrounding 
the Tahoraite clearing. All I noticed during my hasty 
survey of the disk was two small and one large spot, the 
latter close to the limb at about go° (see sketch), and 
surrounded by faculz. 
The moment “totality” occurred I turned my gaze 
towards the sun, and having previously, to save time, 
drawn disks on several pages of my pocket-book, I hur- 
riedly took sketch after sketch of the shape of the corona, 
the rays of which were much better marked than I had 
been led to expect. My object in taking several sketches 
was to record any change in the position of the rays. I 
took five during the short time of totality, and their agree- 
ment is so clear as regards the number and relative 
following 
