244 
NATURE 
[May 9, 1912 
Clouds and Shadows. 
In a letter to Nature (April 18) Mr. Chas. Tilden 
Smith directs attention to a peculiar shadow he noticed 
in the western sky last Easter Monday after sunset, 
and which he no doubt correctly attributed to ‘*some 
unseen object intercepting the sun’s rays,” and so 
casting a shadow on the high and still directly illu- 
minated stratus he mentions. 
Such shadows are by no means uncommon in lower 
latitudes, and are certainly caused either by clouds, 
especially the towering columnar cumuli (so common 
in the Caribbean Sea) or by mountains. For many 
years past the writer has been collecting data regard- 
ing such shadows and working out the position, size, 
and shape of the objects causing them. He has suc- 
ceeded in (a) predicting correctly the form, position, 
and duration of the shadows caused by moun- 
tains for a sunset viewed from a_ known 
position (supposing that clouds did not interfere), 
e.g. from a ship to the east of Cuba, in which 
case it was possible to assign some of the observed 
shadows to definite peaks; and (b) he has succeeded 
in (conversely) deducing from the observed positions 
and forms of these shadows the general configuration 
of the mountain ranges which caused them—e.g. off 
the eastern coast of Brazil. 
Such shadows to be seen well require (1) a clear 
lower atmosphere, and (2) a reflecting layer at a con- 
siderable height—e.g. six miles. 
The writer hopes to be able before long to publish 
these and many other observations and deductions, 
together with the formulz necessary for the analysis 
of this part of a sunset. _ T. C. Porter. 
Upton, Slough, May 3. 
THE ROYAL ACADEMY AND’ NATURE- 
SIMON 
ASHE annual.exhibition of pictures at the Royal 
Academy always affords a-good opportunity 
of examining the works of the several contributors 
as far as they may be considered representations 
of natural phenomena. 
The following notes have therefore been made 
regarding such points as clouds, sun, moon, 
sunset skies, &c., and these are brought together 
under their respective heads. 
Mists. 
163. The Cradle of the Storm. Frank T. Carter. 
The mist or low drifting cloud about the mountains 
is here beautifully portrayed, and the swirl-forms 
indicate local eddies; the lighting is very true. 
190. A Highland Loch, Peter Graham, R.A. Beau- 
tifully graded mists on the mountain sides, and the 
effect of the rift, which is an important feature in the 
picture, is well indicated. 
Cioups (Nimpi or Ratn Ctowps). 
22. The Midlands. C. E. Johnson. 
and colour very good. Excellent representation of a 
rain squall on the right. 
169. The Hunters. C. Napier Henry, R.A. Form 
and colour and general arrangement of the clouds 
quite natural. 
170. Dryslwyn. T. Hodgson Liddell: The cloud 
forms here are accurately shown, but the falling rain 
is not well represented, being not sufficiently trans- 
parent for such a close squall. 
184. A Passage Perilous Maketh a Port Pleasant. 
W. L. Wyllie, R.A. The cloud forms and colour here 
NO. 2219, VOL. 89] 
Cloud forms | 
are very natural, and the reflection on the water 
true. 
189. The Passing Snowstorm. Ernest Procter. The 
clouds here are too dark and coarse. (When looked 
at from some distance the effect is improved.) 
193. Bredon on the Avon. Alfred Parsons, R.A. 
Both form and colour of the clouds beautifully repre- 
sented. A fine cloud study and one to be copied. 
221. Rain Clouds: Bosham. Moffat Lindner. The 
large nimbus is far too solid-looking and lacking in 
detail. Such a cloud in nature is full of detail, both 
in structure and light gradations. As here depicted it 
looks like a lump of dough. 
285. The Approaching Shower. Beatrice Bland. 
Both the clouds and falling rain are well represented. 
The shower, however, is not approaching but travelling 
nearly from left to right, as indicated by the slant of 
the falling rain. 
117. The Approaching Gale. Julius Olsson. The 
clouds and waves are both good in form, but why the 
violet colour in both ? 
359. Stormy Evening on the Cornish Coast. Julius 
Olsson. This picture, like 117 above, is too violet all 
over. 
360. Evening on the Nebelhorn, Bavaria. Edward 
T. Compton. The contrast between the fair weather 
on the right of the picture, the approaching rain 
clouds on the left, and the brightly illuminated snow- 
fields in the foreground is well thought out and ren- 
dered very true. 
Cioups (Cumutt, Fring WEATHER CLoups). 
20. Woodland and Hill. Sir E. A. Waterlow, R.A. 
Very fine representation of clouds with excellent detail 
and gradation. Perhaps some of the upper portions 
of them are not white enough. 
40. The Incoming Tide: Porth, New Quay. .B. W. 
Leader, R.A. Good cloudscape, but must not be 
looked at too closely to obtain desired effect. 
81. Submarines and Torpedo Craft: Old  Ports- 
mouth. W. L. Wyllie, R.A. Most excellent clouds, 
showing the result evidently of much observation. 
Indications of ascending air and upper horizontal air 
currents very natural. Reflection on twater well 
graded. ; a 
115. The Hills of Appin. J. Campbell Mitchell. 
Forms of clouds most unnatural. Too much drawn 
out vertically, and little detail shown. 
162. Marazion Marsh, Cornwall. J. Noble Barlow. 
Clouds badly formed, and, like those in 115, too 
vertical. 
323. The Home of Labour. E. Blair Leighton. No 
idea of cloud form, and lighting all wrong. Clouds 
are drawn out like 115 and 162. 
393. ‘‘The Toiling Year’s Last Breath.” Frank 
Walton. The clouds are good, both in form, detail, 
colour, and gradation. Their lower flat surfaces 
should be horizontal and not all inclined similarly. 
461. The Walls of England. R. Gwelo Goodman. 
Absolutely impossible skyscape. 
582. Spring Sunshine. Alfred Parsons, R.A. The 
cumuli clouds and sky are here very naturally depicted, 
and the artist has blended the sky with the landscape 
most successfully. The tints of the blossoms on the 
trees are true and admirably represented. 
755. A Fine Morning on the Sussex Coast. B. W. 
Leader, R.A. A well-painted and natural skyscape 
with the same proviso as 40. 
129. The Mass at Dordrecht. Moffat Lindner. 
Well-shaped cumuli and good reflections of clouds in 
water. 
198. Skirt of the Dunes at Condette, Pas-de-Calais. 
H. W. B. Davis, R.A. Gradation of blue sky from 
horizon upwards is possibly changed too suddenly. 
