JuLy 23, 1914] 
recognising the high accuracy now attained in elec- 
trical measurements, he concludes that much experi- 
. ment will be necessary before we can hope to introduce 
electrical methods with advantage in place of mag- 
netometers, more especially for field work. 
C. CHREE. 
TIMBER FOR RAILWAY SLEEPERS.' 
ay VALUABLE contribution to the literature on 
‘ Indian timber trees, containing the preliminary 
results of experiments and inquiries initiated at the 
Dehra Dun Institute some three years ago, has lately 
been issued. Research work on timber from an 
economic point of view is necessarily a slow business, 
and years must elapse before final conclusions can be 
reached, but the information already obtained during 
this inquiry indicates clearly that the final results are 
likely to prove of great economic value. 
The memoir is divided into five sections, which 
deal in turn with the physical and mechanical pro- 
perties of Sal timber, its durability, its uses, as well 
as those of the minor products of the tree, the quality 
of the charcoal and fuel, and the yield and prices. 
One point of special interest will illustrate the nature 
of the work in progress and its prime importance. 
Sal is one of the chief timbers employed for railway 
sleepers, and in these days it is surprising to find that 
the majority of the sleepers on Indian lines undergo 
no previous treatment with preservatives—all the more 
so, when one knows how abundant are the insect and 
fungus pests, and how rapid their powers of growth 
and reproduction. This apparent indifference on the 
part of Indian railways to the great economy effected 
in other countries by treatment of the sleepers is not 
easy to explain. It may in part be due to the methods 
used in temperate climates having proved less satis- 
factory when the sleepers are exposed to the hot sun 
of India. But it is also probably due to the natural 
durability of sal, teak, deodar, pyinkado, and other 
woods of this class, which last so long in the natural 
condition, that any extension of their lives by treat- 
ment with preservatives would probably result in the 
resistance to decay becoming greater than the resist- 
ance to mechanical wear and tear, and in this event 
a large proportion of the cost of treatment would be 
money thrown away. 
‘But it is open to question whether such valuable 
woods should be employed for sleepers at all. During 
the past forty years it has been pointed out again 
and again that India possesses several species of 
lower-grade timbers which appear to possess all the 
necessary qualifications for sleepers. Their natural 
durability is low, but this defect can be overcome by 
artificial methods. The fact brought out at the end 
of this memoir, that India is now beginning to import 
Jarrah sleepers from Australia, shows the urgent need 
for testing these lower-grade timbers to see whether 
by treatment they can be rendered equally as service- 
able as sal, teak, deodar, etc. This question is being 
investigated at Dehra Dun on a practical scale, and 
if any of these timbers can be brought into general 
use the economic value of the work will be enormous. 
India will not only be enabled to continue the pro- 
duction of her own sleeper requirements, and to 
employ timbers for the purpose which have no special 
outlet in other directions, but she will also economise 
her more valuable forests of sal alone to the extent 
of some two and a half million cubic feet per annum, 
to say nothing of teak, deodar, pvinkado, and the 
jarrah from Australia. 
1 “On the Economic Value of Shorea robusta, Sal.’ Ry R. S. Pearson. 
Indian Forest Memoirs, Economy Series, vol. ii., part 2, Pp. 70. (Calcutta: 
Superintendent Government Printing, 1913.) Price 35. 
NO. 2334, VOL. 93] 
NATURE , 
345 
Although there is at present little market for sal 
outside India, the steady diminution of the world’s 
timber supply renders it certain that there will be a 
market in the future, when the sdl forests recover 
from past maltreatment, and come into full bearing. 
These facts indicate the importance of the work at 
Dehra Dun, which is being organised on lines that 
must appeal to everyone who has the country’s interest 
at heart. ERA 
OFFICIAL GUIDES FOR GEOLOGICAL 
TRAVELLERS. 
“THE International Geological Congress of 1913 
was indeed fortunate in the reception and sup- 
port accorded to it by the official geological surveys of 
Canada. The guide-books issued for the excursions 
were in reality memoirs on the districts traversed, 
and formed, with their coloured maps and _illustra- 
tions, works of reference for scientific libraries. They 
have now been re-issued for the general public, and 
seven of these handy volumes have reached-us from 
the Department of Mines in Ottawa. 
No. 1, in two parts, covers Eastern Quebec and the 
Maritime Provinces, and is largely of stratigraphical 
interest. No. 2 deals with the eastern townships of 
Quebec and eastern Ontario, including the amphi- 
bolites and limestones of the Bancroft area. The 
metamorphic origin of amphibolites from both igneous 
rocks and limestone, as recognised by Lacroix 
and others in .Europe, is here concisely de- 
scribed. No. 3 is concerned with the neigh- 
bourhood of Montreal and ~~ Ottawa, including 
areas of interesting igneous allkali-rocks, and the 
original locality of the serpentinous marble known as 
Eozoén. No. 4 describes excursions in south-western 
Ontario (where the interest for most geological visitors 
centres in Niagara Falls) and the history of the great 
lake system. No. 5 deals with Ordovician and 
Gotlandian beds in the western peninsula of Ontario, 
and contains a fine illustration of a mass of bedded 
limestone overthrust by ice-pressure on the flank otf a 
Glacial drumlin. We are informed that Nos. 6 and 7, 
on the Toronto region and the rich mining districts 
of Ontario respectively, are issued by the Bureau of 
Mines, Toronto. The Dominion Department of Mines 
in Ottawa, however, is also responsible for No. 8, in 
three parts, and No. 9, which describe the whole 
transcontinental routes from Toronto to Victoria, and 
for No. 10 on Northern British Columbia, the Yukon 
Territory, and the North Pacific Coast. Nos. 8 and 
9, on the Canadian Pacific, Grand Trunk, Canadian 
Northern, and National Transcontinental lines, should 
meet with especial appreciation. 
Such guidance as is here provided for those who 
may be styled ‘‘ post-graduate” visitors shows how 
official surveys may aid in opening up a country 
Seeing that conference with workers from other fields 
is highly stimulating to those who must devote them- 
selves to special areas of their homelands, the encour- 
agement given to strangers is sure to bring a full 
reward. Even in our well-explored islands, descrip- 
tions of districts which have become classical in the 
history of geoloryy might with advantage be issued 
for those visitors who can devote only a few days to 
the ground. We are apt to leave some clever teacher 
or some local enthusiast to extract such matter from 
our detailed official memoirs, and thus to produce a 
compact and reasonable guide. The union of our 
geological surveys, both in Great Britain and in Ire- 
land, with departments concerned with public educa- 
tion suegests that the encouragement of geological 
travel may well lie within their scope. 
