APRIL 15, 1915 | 
NATURE 
177 

amount required by British collieries could be 
readily supplied from Scotland, if railway rates 
of freight could be reduced by 25 per cent. An 
admirably illustrated paper by Mr. P. Leslie deals 
with the afforestation of the coastal sand dunes 
’ at Culbin, between the rivers Nairn and Findhorn. 
The Culbin sands have a remarkable history, as 
they conceal an estate of 3600 acres, which was 
once the richest agricultural district in Moray- 
shire. The incursion of the sand took place 
suddenly in 1694, leaving a wilderness until 1865, 
when Major Chadwick began plantations, which 
have been continued by his son. The species 
mainly used has been been Scots pine, but Corsi- 

The production of potash salts from woodlands 
and wastelands is the subject of a timely article 
by Mr. G. P. Gordon. It is probable that the 
material obtained by burning lop-and-top and 
brushwood in plantations and bracken fern on wild 
hill-sides, together with the ash of furnaces, using 
sawdust as a fuel, can compete successfully with 
kainit, which has been for many years the main 
source of the potash salts that enter into the 
composition of artificial manures. There is an 
account of a peculiar witches’-broom infesting 
willow trees at Hampstead and in parts of Essex 
near London, which appears to be _ hitherto 
undescribed. Prof. A. Henry gives an account, 

iS 

Photo) 
Fic. t.—Culbin Sand-hills, Elginshire : near the Binsness Plantations. 

[Geological Survey. 
The background shows a travelling dune of advancing sand. The 
steep bank with cornice atop and slipping sand on slope, the tails of sand behind the tufts of bent, and the wind ripples in the 
foreground, indicate that the sand-drift is from left to right, #¢., from west to east. 
can pine wherever planted has given the best 
results, producing tall, clean poles of valuable 
timber. The operations, which include the prior 
fixing of the moving sands (Fig. 1) by maram 
grass, are carefully described, and are similar 
to those used by the French in the Landes. 
Wood-charcoal and its uses is the subject of 
an article by Mr. W. D. Ashton Bost, who states 
that the only firm in Britain which reduces iron-ore 
by charcoal is that of Messrs. Harrison Ainslie. 
Their charcoal furnace at Backbarrow on the river 
Leven in Cumberland produces annually about 
2400 tons of so-called “Lorn” charcoal pig-iron, 
which is the dearest iron in the market, and is 
exported for special uses to all parts of the world. 
NO. 2372, VOL. 95] 

from Japanese sources, of the distribution of 
Larix leptolepis in its native home. 
Many useful notes from continental sources are 
given, of which the following may be cited, taken 
from the Norwegian Manual of Silviculture by 
Barth :—The limit of the existence of forest trees 
in Norway is fixed by the mean temperature of 
the four months of vegetation, June to September. 
Birch is content with a mean summer temperature 
of 45° F.; aspen and grey alder with one just 
under 46°F.; Scots pine and spruce, 47°F.; 
Alnus glutinosa, 54°F.; oak, 55° F.; and beech, 
56°F. It would be interesting to obtain similar 
figures regarding the limit of these species and 
larch in Britain. 
