582 

which comprises 63 stations, and in addition to the 
Egyptian and Sudanese stations, it includes seven 
stations in Cyprus, one in Crete, and one in Abyssinia. 
Many of the normals cover a period of 20 years. 
Normals for rainfall are given for 76 stations, for the 
total number of years for which trustworthy records 
are available. It is said not to be uncommon, 
especially in the Sudan, for the relative humidities 
to fall below ro or even 5 per cent. Wind force 
given throughout is stated to be in terms of numbers 
on the Beaufort scale. The scale is given as 0-10, 
but Beaufort scale should be 0-12. The equivalents 
in miles per hour given for the scale o—Io is in fair 
agreement with the Beaufort values o-10 given by 
the British Meteorological Office. The percentage 
frequency of wind direction is given for most stations. 
Most of the Egyptian stations have single louvred 
screens; this seems scarcely satisfactory, especially 
for a hot country. Monthly maps are given for 
isobars and prevailing winds, for air isotherms, and 
for rainfall. The tables of normals are of great 
value to the world’s meteorology. The absolutely 
highest temperature on a single day at many stations 
exceeds 120° F. and in places even touches 130° F, 
On the coldest day in winter frost is exceptional in 
the shade to the south of 20° N. Rainfall for a single 
day is occasionally more than the average total fall 
for the month; there are two instances of 11 inches 
and more in the 24 hours—at Alexandria in December 
1888 and Tombé in the Sudan in July 1914. A rain- 
fall map intended as a frontispiece will be issued 
separately. 
PEAT IN THE UNITED StTaTEs.—Though peat is 
still looked on with hesitation as a source of industrial 
fuel in the near future, every national geological sur- 
vey is attracted by the numerous schemes for its 
exploitation. That of the United States has issued 
Bulletin 728, on “ The occurrence and uses of Peat 
in the United States,’ by E. K. Soper and C. C. 
Osborn (1922). The maps record very considerable 
deposits in the regions of more temperate Climate, as 
in Minnesota towards the Canadian border. It is 
pointed out that, contrary to popular belief, the 
Mississippi basin is poor in peat, owing to the high 
temperature, which accelerates the decay of vegeta- 
tion, and the frequent floods, which deposit sheets of 
alluvium. Some of the plates illustrating the infilling 
of basins of various types introduce unusual scenes, 
such as the Dismal Swamp, with its decaying forest, 
in the Virginian coastal plain. When we come to the 
treatment of peatlands for raising crops, we find that 
the customary advice is given, to clear away the 
upper peat as much as possible, to drain thoroughly, 
and to add materials that will provide the land with 
something like a reasonable soil. The case is familiar 
to us through agriculture in the English fenlands. 
The Bulletin forms a good handbook for the apprecia- 
tion of lowland peat-deposits by the student. 

GENETICS OF Propuctiviry.—In a study of pro- 
ductiveness in apple trees, Sax and Gowen (Bull. 305, 
Maine Agric. Expt. Sta.) show that this quality is 
closely associated with habit of growth, although soil 
differences in an orchard also play a part. They also 
show (Bull. 307) that many commercial varieties of 
apples are self-sterile and that insect visits are essential 
for the setting of fruit. They recommend the inter- 
planting of different varieties which are inter-fertile 
and flower at the same time. In two other papers 
(Bulls. 301 and 306) on milk production in Holstein- 
Friesian cattle, a further study is made of the trans- 
mitting powers of sires for milk production, and 
of the relative merits of a 7-day or a 365- 
day test for the relation between milk yield and 
NO. 2791, VOL. 111 | 
NATURE 

[Aprit 28, 1923 
percentage of butter-fat. That the daughters of 
different sires inherit differences in their milk pro- 
duction is well known. But pedigree results show 
that the cattle breeder’s principle that “like begets 
like ” is not a sufficient one to follow in breeding for 
milk production. 
+ 
Movutps on Meat 1n Cotp StoracE.—On behalf 
of the Food Investigation Board, F. T. Brooks and 
M. N. Kidd recently published, in Special Report 
No. 6 of the Board (1921), an account of the “ black 
spot ’’ produced upon meat in cold storage by the 
activity of moulds. In this report it was demon- 
strated that the moulds responsible for the discolora- 
tion could grow and reproduce, although the meat 
was kept at -6°C. F. T. Brooks and C. C. Hansford 
have now published the more interesting mycological 
results of this valuable piece of applied research in 
the Transactions of the British Mycological Society, 
vol. 8, Part III., pp. 113-142, 1923. They conclude 
that Cladosporium herbarum is the species responsible 
for all the cases of ‘‘ black spot ’’ on meat they have 
observed, and that Hovmodendyon cladosporiodes is 
identical with it. This Cladosporium appears to 
occur very generally on vegetable refuse as well as 
on meat, and to be very variable in habit, so that a , 
careful control of its structure and growth on a wide 
range of culture media is necessary for its identifica- 
tion. Many of its forms appear to have been de- 
scribed as species. Among the other moulds growing 
on cold stored meat two new species, Sporotrichum 
caynis and Torula botryoides, have been isolated ; 
while on one occasion a new genus turned up in a 
woolly patch of mould present on a consignment of 
skinned Australian rabbits. In view of the laboratory 
from which the present work is issued, it is appropriate 
that the authors have named the new genus Ward- 
omyces in memory of the late Prof. Marshall Ward. 
THE SPREAD OF RUSTS UPON CEREALS.—With work 
proceeding for the new Ph.D. degree at many British 
Universities, we shall probably have many theses 
published in which essentially British problems are 
materially elucidated by overseas investigators. 
Certainly Karm Chand Mehta, now professor of 
botany at Agra College, India, as a result of his work 
at Cambridge under the direction of Mr. F. T, Brooks, 
has given us a most valuable study of the methods 
by which cereals are attacked year after year by the 
various species of the rusts (now published in the 
Trans. Brit. Mycological Soc., vol. 8, Part III., 
Pp. 142-176, 1923). The rusts are quite unable to grow 
as saprophytes, hence there is great difficulty in 
their continued maintenance in pure culture, and 
much discussion as to the method by which these 
fungi maintain themselves through the winter when 
their normal host plant is harvested in the autumn. 
These parasites were some of the first microscopic 
forms in which a well-marked life cycle was traced 
with essential stages in two separate host species, 
often plants of widely different nature, and in the 
case of the black rust of wheat, Puccinia graminis 
Pers., the present paper supplies further evidence for 
the truth of an oft-contested thesis that the wheat 
plants may be infected from the accidial stage upon 
the winter host, the wild barberry. In the case of 
the other rusts of wheat, brown rust, P. ¢riticina 
Erikss., and yellow rust, P. glumarum Erikss. and 
Heun, the observations and experiments here recorded 
show the significance of the self-sown seedlings of the 
wheat left in the ground after the harvest ; 
these the fungus persists and the uredospores formed 
upon them are the main source of infection of the 
new crop. This paper, as some earlier classic papers 
from the Cambridge laboratory, is fundamentally 
upon — 
