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NATURE 
[AUGUST 15, 1912 
are those of iron, and the Lake Superior region is 
still the mainstay of the American industry. The 
Mesabi district has now the largest output of the five 
mining fields near Lake Superior, and yields 543 per 
cent. of the total for the United States. 
The five new bulletins on American economic 
geology deal with problems as varied as the subject 
is vast. Mr. Munn brings forward fresh evidence in 
support of his views on the inapplicability of the anti- 
clinal theory of subterranean oil storage to the Penn- 
sylvanian oil fields. His memoir on the Foxburg 
and Carnegie districts shows that the folds are not the 
main agency in determining the distribution of the oil. 
Thus near Carnegie the oil sands, which are really 
sandstones, occur in many levels in the Devonian and 
Carboniferous systems; the beds are gently folded, 
and if the oil collected along the folds the successive 
oil sands should be most productive along the same 
lines; but their chief supplies come from different 
localities. The anticlinal theory is still less tenable 
for the Foxburg district, as the oil-bearing beds are 
there nearly horizontal. The oil occurs in pools, the 
distribution of which is shown on a most interesting 
map. Mr. Munn attributes the collection of the oil in 
these patches to the pressure of descending water, 
which slowly percolates through the less permeable 
beds; it thus forces the oil downward, and then later- 
ally into the most porous beds, where the movement 
of water due to capillary attraction is least powerful. 
Mr. Weed has. compiled a valuable survey of the 
copper ores of the Atlantic coast States. Students of 
copper ores will read with interest his account of the 
famous copper mines of Ducktown, and also his con- 
vincing arguments that the ores in the Triassic sand- 
stones were derived from the associated basic lavas 
and sills known as the New Jersey ‘traps.’ 
The bulletin on Alaska (No. 480) includes fifteen 
reports by various authors on the coal, water supply, 
and ore deposits. The most generally interesting 
report is a general summary by Mr. Brooks of the 
results of thirteen years’ surveys of the Alaskan 
metalliferous lodes. The mineral output of Alaska is 
still: increasing, though there has been a set-back to 
the development of the coalfields, the yield of which 
has fallen to half, to the great detriment of commer- 
cial progress in the territory. The Alaskan railways 
are paying for imported coal from three to four times 
the price for which they should obtain better local 
material. The closing of most of the coal mines 
appears to be due to the legislation forced on the 
western mining States by the anxious eastern States, 
owing to the agitation for the conservation of natural 
resources. Closing the mines is certainly the most 
effective method of conserving the mineral reserves of 
a country, though it may be equally effective in secur- 
ing their ultimate waste. J. W. G. 
THE NUTRITION OF FARM ANIMALS. 
ee spite of the enormous importance of the live-stock 
industry in Great Britain, very little work has 
been done on the nutrition of farm animals, nor have 
physiologists drawn upon the accumulated knowledge 
of practical feeders to anything like the extent war- 
ranted by the interest of the subject. This last fault 
will, it is hoped, be remedied at the forthcoming 
meeting of the British Association, when physiologists 
and practical feeders will both attend at the Agri- 
cultural Section for a discussion on the problems in- 
volved. With the extension of the Agricultural School 
at Cambridge we may hope also for a considerable 
increase in our knowledge of animal nutrition. 
For some time past nutrition studies have been 
going on at the Wisconsin Experiment Station, the 
NO. 2233, VOL. 89| 
results of which are published in the research bulletins 
of that institution. Messrs. Hart, McCollum, Steen- 
bock, and Humphrey have recently (Bull. No. 17) 
issued an account of experiments carried on for four 
years with heifers, showing that rations possess im- 
portant physiological values not measurable by present 
chemical methods. Animals fed on rations chemically 
alike (i.e. containing equal amounts of fat, protein, 
&c.), but derived from different sources, behaved very 
differently. This result has already been obtained 
elsewhere, but the further conclusions of the authors 
are rather remarkable. Maize was the best nutrient, 
oats came next, and wheat last. When a mixture of 
all three was used, the animals responded less vigor- 
ously than to the maize or oat rations alone, but 
better than to the wheat ration. Certain other effects 
were noted also; the urine of the wheat-fed animals 
was acid to litmus, that of the others was neutral or 
alkaline. It is difficult to account for these observa- 
tions if further experiment shows them to be well 
founded; on other grounds it might have been expected 
that the mixture would have given the best result. 
In another paper (Bull. No. 21), McCollum and 
Steenbock show that rather different results are ob- 
tained with the pig. Wheat, oats, and maize did not 
show such wide differences in chemical value as were 
expected from the chemical differences in the proteins. 
It is known, however, that the pig has a remarkable 
power of effecting the most unexpected changes during 
the course of its metabolism, transforming into pork 
an astonishing variety of substances. Marked in- 
creases in body protein were obtained when casein 
was fed as the only protein; zein, however, failed to 
increase the body protein, although the animal utilised 
nitrogen from this source for repair of the losses due 
to tissue metabolism. ‘The authors conclude that the 
repair processes are of different character from the 
processes of growth, and do not involve the destruction 
and re-synthesis of an entire protein molecule. 
Recent issues of the Journal of the Board of Agri- 
culture have contained a series of papers by Dr. 
Crowther, which summarise admirably our present 
knowledge of the scientific and economic principles 
involved in animal feeding. It is clearly shown that 
no one set of considerations determines the value of a 
particular ration, and in the present state of our 
knowledge the recommendations of the man of science 
can only be taken as the starting point from which 
to begin feeding trials. Even the best methods of 
calculating rations are shown to be only roughly 
approximate. 
RECENT WEATHER. 
NE of the many interesting vagaries of the 
recent weather, with its midday temperatures 
from 20° to 30° lower than for the corresponding 
period last year, has been the persistently higher 
temperatures over Scandinavia than in other parts of 
western Europe. Averaging the maximum _ shade 
readings at several representative stations reporting 
to the Meteorological Office, this abnormal result is 
shown to have prevailed, so far, throughout August. 
For the first twelve days of the month the average 
maximum temperature at Haparanda, at the head of 
the Gulf of Bothnia, only just outside the Arctic 
Circle, is 76°8°. The mean for the same period at 
Nice is 791°; but Lisbon is only 73°7°, or lower than 
Haparanda by 31°. At Bodé, within the Arctic 
Circle, the mean of the highest day readings was 
670°. At Biarritz the mean of the maxima was only 
69°8°, Paris 676°, Brussels 67°5°, London 64’5°, 
Jersey 633°, Liverpool 60°3°. The difference is even 
more intensified taking the mean of the maxima, or 
eS OEE 
