APRIL 23, 1914] 
NATURE 
19I 
African bulbs and ground orchids than has yet 
been brought together in one place is already 
established in the nursery. Most of these were 
introduced here during the winter rains, which 
have been followed by an _ exceptionally wet 
summer. The results are such that any doubt 
that may have been entertained as to the possi- 
bility of establishing here a representative collec- 
tion of South African—one may almost say African 
—plants is set at rest. 
Most of those who have taken an active part 
in the foundation of these gardens will not be 
satisfied merely with the collection and cultivation 
of South African plants. The educational effect of 
such a collection will nevertheless not be small. 
The great extent of the country and the sharpness 
of its physical divisions militate against the slowly 
growing sense of national unity. The presenta- 
Group of Aloe succotrina. 
plant association about five acres in extent, on a steep slope strewn with large blocks of Table- 
Fic. 3-—National Botanic Gardens. 
mountain sandstone, 1500 ft. s.m. 
moisture-loving annuals, ferns and mosses. 
tion, even on a small scale, of typical representa- 
tives of its regional floras to the view of many who 
of necessity are acquainted with but little of its 
area, must do something towards the obliteration 
of hard dividing lines. 
From a purely scientific point of view, the im- 
portance of the National Botanic Gardens depends 
upon the use that is made of them for purposes of 
investigation. It is clearly realised that they will 
fall short of justifying their existence if they fail 
to make adequate provision for the proper study 
of the material they contain. Whether this. pro. 
vision will come through the much-needed univer- 
sity, or partly or entirely by private benefaction, 
or through some other channel, remains to be 
seen. The work at present in progress is ordered 
on the assumption that such provision will be made 
in the near future. 
Since the publication of Pappe’s “Flore 
capensis Medica Prodromus ” (1850), it has been 
NOjee2n, VOL. 93} 
This is part of a very remarkable 
Associated with the aloes are lichen-covered trees of Olea 
verrucosa, Cunonia capensis, Maurocenia frangularia, Plectronia sp., etc., and a number of 
known that a very large number of native species 
are, or have been, in use locally for medicinal 
or other domestic purposes. Plants yielding 
essential oils and other products of probable or 
possible economic value are numerous. While 
much of the work of acclimatisation, which in tropi- 
cal countries has. been done by the Botanic 
Garden, is here receiving adequate attention in 
the departments of agriculture and forestry, there 
are yet very many exotic plants worthy of atten- 
tion, the possibilities of which await investigation. 
Among these the drug- and perfume-yielding 
species of the Mediterranean region are conspicu- 
ous. The economic garden, for which some twenty 
to thirty acres have been reserved, should there- 
fore become an important part of the establish- 
ment. 
The functions assigned to the National Botanic’ 
Gardens cover a wide range. At 
present much of the equipment 
which will make it possible to 
fulfil them is to seek. But the 
gardens exist in response to a 
popular demand, and popular sup- 
port to make their future secure 
will not be wanting. 
WAVES .IN SAND . AND 
SNOW. 
R., VAUGHAN’. CORNISH 
has written a charming book, 
full of interesting observations. 
He starts with descriptions of 
waves and ripples in blown sand, 
and passes later to the similar 
forms produced under water, giv- 
ing many good photographs to 
illustrate their various character- 
istics. Whether the waves are 
large or small, or whether formed 
by wind or water, it is obvious - 
that the same causes are at work, 
and the author rightly distin- 
euishes these waves from drifts 
and sand banks, the latter having 
their lengths parallel to the direction of the aver- 
age stream, while the ridges of the waves are at 
right angles to it. The origin of the lateral drift 
which gives rise to sand-banks was first explained 
by W. Froude and independently by Prof. James 
Thomson about the same time. 
Snow waves and snow drifts, and other forms 
of accumulations of snow, are described in chap- 
ters iii. and iv., and these also are well shown 
by photographs. The phenomena of snow are 
much more complex than those of sand, both on 
account of the variable size of the snow-flakes 
and particles and of the varying conditions as to 
moisture and temperature in which they are de- 
posited. In some states snow particles cohere on 
contact; in others when the temperature 1s low 
they behave more like a dry powder, and it re- 
1 ‘* Waves of Sand and Snow and the Eddies which Make Them.” By 
Dr. Vaughan Cornish. Pp. 383+plates. (London: T. Fisher Unwin, n.d.) 
Price 1os. net. 
