Marcu 26, 1914] 
NATURE 
83 
Yale Forestry School, had formerly practical ex- 
perience in the lumber camps of the United 
States and Philippines; and in consequence has 
been able to give a readable account of the numer- 
ous logging methods which are actually in opera- 
tion. The book should prove suggestive to owners 
of timber lands in our own Colonies and to Indian 
foresters. 
The first part is general, and comprises chap- 
ters on the resources and protection of the forests 
of the United States. The original woodland area 
is estimated at 850,000,000 acres, containing 
about 433,000,000,000 cubic feet of timber. The 
existing forest has shrunk to 550,000,000 acres, 
estimated to contain 210,000,000,000 cubic feet, 
of which the Federal and State Governments 
control about one-fourth. The second part deals 
with felling of timber, and contains chapters on 
labour, tools, organisation of the camp, careful 
wiiisation of the tree, etc. The third ‘part’ is 
devoted to transport by land, and is very complete, 
giving an account of aerial cables, railways, 
timber slides, and shutes, etc. The rude but effica- 
cious system, by which railroads are often built 
in the forests of the Far West, is carefully de- 
scribed. The fourth part, transport by water, 
treats of floating, rafting, flumes, sluices, etc. 
Another part entitled “Minor Industries,” deals 
with tapping for turpentine, harvesting of tan- 
barks, etc. A glossary of terms used in logging, 
tables of wages, timber values, etc., complete this 
admirable text-book. 
Foods and Household Management. A Textbook 
of the Household Arts. By Prof. Helen Kinne 
and Anna M. Cooley. Pp. xv+4o1. (New 
York: The Macmillan Company, 1914.) Price 
5S; net. 
A FULL treatment is provided in this volume of 
the production, cost, nutritive value, preparation, 
and serving of a great variety of foods. The 
relation of these topics to general. household 
management is made clear, and a careful study 
of household accounts, methods of buying, and 
ordinary housewifery is included. Though some 
parts of the book deal particularly with American 
conditions, most of the chapters make a direct 
appeal to teachers of domestic subjects in this 
country, and the volume deserves their attention. 
The Continents and their Pecple. South America. 
By J. F. Chamberlain and A. H. Chamberlain. 
Pp. ix+189. (New York: The Macmillan 
Company, 1913.) Price 3s. 
Tuis beautifully illustrated reading book will serve 
admirably to supplement the ordinary text-book in 
use by children studying the geography of South 
America. The physical and human aspects of 
geography are presented in such a way as to 
interest young pupils and to encourage them to 
trace the connection between the two. There are 
only three maps in the book; one is an old- 
fashioned coloured plate, another a_photo-relief 
map of the continent, and the third a sketch map 
showing rainfall. 
NO.w2ok7, VOL, 93, 
LERLERS, LO)". THE, EDITOR: 
[The Editor does not hold himself responsible for 
opinions expressed by his correspondents. Neither 
can he undertake to return, or to correspond with 
the writers of, rejected manuscripts intended for 
this or any other part of Nature. No notice is 
taken of anonymous communications. | 
The Movements of Floating Particles. 
In reply to Mr. Archdall Reid (March 19, p. 60) I 
should say that the effects which he describes are the 
natural behaviour of a contaminated surface. A 
greasy contamination of the right order of magnitude 
tends to spread itself uniformly over the surface. If 
when the liquid in the saucer sways over to one side, 
the surface layer went with it, the contamination 
would be concentrated upon that side and diluted upon 
the other. Such a displacement is resisted. The 
invisible surface contamination remains nearly equally 
distributed, and the fact is witnessed by the visible 
particles floating upon it. R. 
Weather Forecasts. 
In Nature of February 26 Mr. Mallock verifies the 
forecasts for London during 1913. He selects four 
characteristic types accompanying shifts of wind, and 
finds that the verification did not exceed 58 per cent. 
The temperature forecasts were even less accurate, 
being correct only 161 times; and while the given per- 
centage is 52, a truer value, including doubtful and 
‘“no”’ forecasts, would be 44. He then, very properly, 
raises the question, reduced to its simplest terms, ‘Is 
the daily chart with its many entries worth while?” 
Personally Mr. Mallock thinks it extremely improb- 
able that trustworthy forecasts can be made. Many 
meteorologists share this opinion. Two deductions 
can be drawn, either the chart does not contain data 
suitable for trustworthy forecasting, or the men who 
forecast are not competent. The latter we can quickly 
dispose of, for there is no difference of opinion regard- 
ing the honesty and professional skill of the staff of 
the Meteorological Office; and incidentally we may 
acknowledge the steady rise of the office under Dr. 
Shaw’s progressive leadership to a commanding place 
among the meteorological services of the world. 
Then is the weather chart inadequate? Yes. More- 
ever, it will be so for years to come. On the 
other hand, too much may be expected, and a method 
of verification applied that is entirely too rigorous. 
Weather is not the only subject on which forecasts are 
made, and if these were rigorously tested there would 
be many verifications below 50 per cent. Not long 
ago, the writer had gently to remind the editor of a 
' metropolitan daily ‘‘that the forecaster in his state- 
ments concerning things that had not yet happened 
was more accurate than the Press (in general) in its 
statements concerning things that had already hap- 
pened.” Errors in law, medicine, and engineering are 
neither unknown nor infrequent. 
To ask for a definite statement of weather conditions 
twenty-four hours in advance, is asking much in view 
of the number of indeterminate variables that are 
operative. Pressure, temperature, air motion, and pre- 
cipitation are net definite, regular processes, but often 
erratic and complicated. From our knowledge of the 
laws of gases we may indeed work out certain func- 
tional relationships, but we are still far from determin- 
ing actual interferences due to circulation, absorption, 
and radiation. 
Shall the chart then be abandoned, and shall we 
