98 NATURE 
[JANUARY 20, 1923 

an interesting group of willows which, inundated 
for more than a metre above their normal root level, 
have developed a fresh crop of roots at the new 
water level, increasing the girth of their trunks above 
this new fringe of roots. 
Very few plants replaced the displaced vegetation, 
and when the water retreated the mud was left bare 
and desolate. Massart describes the red alga, 
Porphyva laciniata, growing in the brackish water 
of a shell-hole, but no longer red in colour. _ Fringing 
the salt inundation were typical halophytes. like 
Aster tripolium, Atriplex littoralis, etc. As the waters 
receded and the former denizens returned to the 
attack these plants have to retreat—in 1919 in the 
ascendant throughout the region, 1920 finds them 
fighting desperately for a foothold upon the salt- 
incrusted edge of many a shell-hole. Active in the 
attack upon these war-time invaders is Agropyrum 
repens, a plant the fighting qualities of which are known 
to many an allotment holder. Phragmites communis 
had maintained itself during the inundation upon 
occasional islets rising above the general flood level, 
where it dispossessed practically all other inhabitants 
trying to maintain themselves before the salt flood. 
*As the mud dries, long slender rhizomes descend 
from these little knolls and Phragmites eagerly 
advances to recover its old domain. An interesting 
observation made by Massart is that as the yellow- 
flowered halophyte Aster tvipolium, typical of the 
salt marsh, recedes before the reconquering flora of 
the fertile Belgian plain of peace, there is a fringe 
of the form of this aster with”purple-ray florets to 
be found maintaining itself for a time upon the more 
fertile, less saline soil. This occurrence of the 
purple form is being made the subject of further 
study in a biological laboratory installed upon the 
Yser. 
Another result of the war is that some of the earlier 
scientific communications, republished from French 
scientific journals, give the observations made by Prof. 
Massart in his enforced exile during those tragic 
years, including a most interesting discussion of the 
striking features of the Riviera vegetation as they 
appear to a Belgian ecologist. The reprinting of 
Prof. Massart’s polemical contribution to the Revue 
de Paris of October 1918, “‘ Les Intellectuels Allemands 
et la Recherche de la Vérité,”” seems inappropriate in 
a volume of this nature, but the perusal of this 
article may be recommended to any British botanists 
who may have so far failed to realise the difficulties 
that still lie in the way of any genuine international 
Botanical Congress, of the type that would have 
been held in London before the present date if th 
war had not intervened. : 
Methods and Costs of Coal-mine Haulage. 
By Prof. Henry Louis. 
‘THE series of bulletins issued under the authority 
of the University of Illinois has achieved an 
enviable reputation among mining engineers in this 
country, and the latest addition fully sustains this 
reputation. Its origin differs slightly from preceding 
bulletins, inasmuch as it has been prepared under a 
co-operative agreement between the Engineering Ex- 
periment Station of the University of Illinois, the 
Illinois State Geological Survey, and the United States 
Bureau of Mines. Incidentally, such a method of 
work may be recommended to the serious attention 
of universities in this country; some of them have 
indeed moved in this direction, but none has gone so 
far as has the University of Illinois. 
The present bulletin could scarcely come at a more 
opportune moment, seeing that attention in this 
country is being focussed upon the possibilities of 
electric locomotive haulage in collieries, and the 
pamphlet under review contains a full and authori- 
tative exposition of what is being done in one of the 
most important of the coal-mining regions of the 
United States, Illinois ranking in coal output next to 
Pennsylvania, with an annual production exceeding 
one-third of that of Great Britain. Individual mines, 
moreover, are very large, seeing that in some of them, 
as is here stated, “‘ 6000 or more tons of coal per day 
are hoisted in 5-ton capacity cars and that 1200 or 
more cars per day, or 150 per hour,’”’ must be con- 
centrated at the shaft bottom from various parts of 
the mine; there is nothing on the same scale in this 
country. 
The bulletin is divided into six chapters. The first 
contains merely a brief introduction and explanation 
of the scope of the subject. The second chapter deals 
briefly with the evolution of mine haulage and shows 
how great has been the change in practice within the 
last twenty years: ‘‘In 1899, 87-1 per cent. of the 
tonnage in Illinois coal-mines was handled by animal 
} Engineering Experiment Station, University of Illinois. Bulletin No. 
132: ‘‘A Study of Coal-mine Haulage in Illinois,” by H. H. Stoek, J. R. 
Fleming, A. J. Hoskin. 
NO. 2777, VOL. 111 | 

haulage. Locomotives hauled 2-5 per cent., ropes 
7°9 per cent., and tramming 2:5 per cent., but in 1921 
it appears that both ropes and tramming were prac- 
tically obsolete and that 91-2 per cent. of the coal 
was moved by locomotives, and only 8-8 per cent. by 
animals.”’ 
Of the locomotives, by far the greatest number are 
electric ; considerable attention is now being paid to 
the track, 45- to 60-pound rails being used on the 
main roads. It appears that the first electric loco- 
motive was tried in a colliery in Illinois so far back as 
1888, but their introduction on any scale only came 
eleven years later. These locomotives were trolley 
locomotives and could only run on main roads; 
gathering from the coal face was still mainly done by 
mules, but in 1900 the cable locomotive was intro- 
duced, consisting of a locomotive furnished with a 
long flexible conducting cable carried on a reel, which 
enabled it to run on rails not equipped with trolley 
wires. For steep dips crab locomotives have been 
used, consisting of a locomotive with a separate motor 
driving a drum carrying a steel winding rope, by 
means of which cars could be hoisted up gradients 
too steep for the locomotive to travel. Another 
method of getting over the latter difficulty was the 
introduction of the rack-rail locomotive, similar to the 
type used on certain mountain railways. 
Storage battery locomotives were introduced about 
1899, and they have gradually been improved until 
their use is now very general; they are so built that 
they are considered quite safe for operation even in 
gassy mines. Other types of locomotives that are, 
or have been, used are steam locomotives, compressed 
air locomotives, and petrol locomotives; curiously 
enough, the so-called fireless locomotive using super- 
heated water, which is quite popular in German 
collieries, appears never to have been even considered, 
although it no doubt presents certain advantages in 
fiery mines. 
The third chapter of the bulletin deals with the 
lay-out of the shaft bottom ; this section is of com- 
