250 
Treatment of infected soils with formalin 1:50 has 
been found efficient in checking the disease, but from 
the point of cheapness and efficiency steam-heating is 
recommended. Certain secondary effects, such as the 
killing of weed seeds and the destruction of insect 
pests in the soil, and greatly increased size and vigour 
of plants grown in treated soils, were also noted. 
In a recent Bulletin of the U.S. Weather Bureau 
the Rev. M. Saderra Masé describes an interesting 
series of earthquakes which occurred in the sub- 
province of Benguet (Luzon) in August and Septem- 
ber, 1913. They were very numerous (about 350 
occurring in little more than a month), as a rule of 
slight intensity, and, even with the strongest, of 
very small disturbed area. It is probable that they 
originated at a very slight depth. As the earth- 
quakes occurred at the close of the rainy season, in a 
limestone district in which the annual rainfall. is 
about 160 inches, and in which there are frequent 
subsidences of the ground, the author concludes that 
the earthquakes are neither tectonic nor volcanic in 
their origin, but probably due to underground rock- 
falls and secondary faults. 
Tue Meteorological Office of Canada has recently 
issued an_ interesting monograph, ‘‘ Canadian 
Weather Forecasting,’? as an addendum to ‘Gales 
from the Great Lakes to the Maritime Provinces,”’ 
covering the years 1905-12, prepared by Mr. B. C. 
Webber, under the superintendence of the director 
of the Meteorological Service. In a preceding mono- 
graph for the period 1874-1904 Mr. Webber suggested 
some aids to assist the forecast officials, and these 
have now been supplemented, and the tables show, 
in addition, the percentages of low-pressure areas 
causing storms in various months and districts and 
the directions in which the depressions moved, to- 
gether with other useful information. November is 
the most stormy month on the Great Lakes during 
the season of navigation, but January and February 
are the stormiest in the Gulf of St. Lawrence and 
the Maritime Provinces; March is not an unusually 
stormy month. Within the eight years in question 
the area of the Canadian weather map has been 
much enlarged, and knowledge of movements of high- 
and low-pressure areas has been enhanced by the 
introduction of a daily meteorological chart of the 
northern hemisphere since January 1, 1912. It is, 
however, reluctantly admitted that the advancement 
of weather forecasting has been more or less dis- 
appointing. The author considers that the study of 
the upper air and of solar physics will eventually 
undoubtedly assist in solving some of the vexed 
problems which confront the meteorologist. 
THE necessity of bringing modern mathematical 
concepts within the range of study of comparatively 
elementary students has led Mr. C. Elliott, of King 
Edward VII. School, Sheffield, to produce a book of 
116 pages, entitled ‘‘ Models to Ilustrate the Founda- 
tions of Mathematics”’ (Edinburgh: Lindsay and Co., 
1914, price 2s, 6d.). It consists of four chapters deal- 
ing respectively with the meaning of correspondences, 
multiplexes, spaces defined as ordered multiplexes, 
correspondence of operands to functions, and multiple 
NO)- 2323, MOL. 931 
NATURE 
[May 7, 1914 
correspondence. Although a selection of classificatory 
models was exhibited at the 1912 Mathematical Con- 
gress, the use of the term ‘‘models’”’ in the title of 
this book may perhaps be rather misleading, for it 
consists mainly of definitions and explanations, and 
the nearest approach to models generally consists in 
mere references to illustrations of classes, like and un- 
like things, correspondences, and so forth, where these 
can be exemplified by objects of everyday life. The 
question as to how far the subject can be understood 
and appreciated by schoolboys is a very interesting 
one. 
Tue first of a series of illustrated articles descriptive 
of a 300,000-h.p. hydro-electric plant on the Mississippi 
appears in the Engineer for May 1. These works are 
situated at Keokuk, on the Iowa side of the river, 
about 130 miles north of the mouth of the Missouri 
River, and 137 miles from the city of St. Louis. One 
purpose of the power development is to deliver cur- 
rent in large quantities to distant points by trans. 
mission lines up to 200 miles in length, and in August 
last the supply of current to St. Louis was com- 
menced. The electric light and tramway company of 
St. Louis has contracted to take 60,000 h.p. for a 
term of ninety-nine years. The works comprise three 
main sections. First, a dam 4700 ft. long, extending 
from the east bank at Hamilton to within a thousand 
feet of the west bank at Keokuk. Secondly, a power- 
house, extending downstream from the end of the 
dam for a length of 1700 ft. Thirdly, a dam extending 
from the lower end of the power-house to the west 
bank, forming the fore-bay and having a large single- 
lift lock for navigation, The total length of mono- 
lithic concrete construction is more than two miles. 
The working head of water available for the machines 
ranges from 23 to 40 ft. 
OUR ASTRONOMICAL COLUMN. 
May MereorS.—It is hoped that favourable condi- 
‘tions will be experienced for the observation of Coronid 
meteors in May. Mr. W. F. Denning directs atten- 
tion to this shower in Astronomische Nachrichten, 
No. 4726. In recent years he found the chief radiant 
point to be about 246°+ 30° near ¢ Corone, and a few 
degrees west of p Herculis. According to his observa- 
tions in 1903 and 1911, the meteors were white, swift, 
and usually trainless. The most suitable time for 
their observation is between May 18 and 26, and the 
absence of the moon will render the observation more 
easy. 
ComET 1914a (KRITZINGER).—The following is the 
continuation of the ephemeris of comet 1914a (Kritz- 
inger) which was given in this column last week, the 
information being gathered from Prof. H. Kobold’s 
communication to the Astronomische Nachrichten, 
No. 4729 :— ; 
12h, M.T. Berlin. 
R.A. (true) Dec. (true) Mag. 
mss ‘ 4 
May 7 18 46 9 +23 29:0 
Ole Aisa: 50057 Zar 25:0," sae 
Q -«-- 55 45 25 21:9 
10 IQ O 34 26 16-7 
I Caoy 27 10-4 
10 14 28 2:3- «eemoue 
13 15 4 28 53°9 
14 19 29 54 +29 43-6 
