M.—AGRICULTURE 247 
mapping soils on a climatic basis, and soil surveys on the new basis were 
soon begun in a large number of European countries and in the United 
States. At the International Soil Congress held at Rome in 1924 it was 
agreed to construct a soil map of Europe, and in 1926 the special committee 
representative of the different countries concerned met in Hungary to 
discuss in the field the practical details of the work on which the map 
was to be based. At a subsequent meeting in Budapest the details of 
the methods were adjusted, and it was agreed to undertake the construction 
of a map of the soils of Europe based on as uniform a method of surveying 
as possible. The ‘ General Map of the Soils of Europe,’ under the 
editorship of Prof. Stremme, Danzig, was published in 1927. The 
English text, translated by Dr. W. G. Ogg, of the Macaulay Institute for 
Soil Research, Aberdeen, was published in 1929 with the aid of a grant 
from the Department of Agriculture for Scotland. The first edition of 
the map is on the scale of 1 : 10,000,000, and preparations for a second 
edition are in progress. 
The idea of a soil map of Europe is an ambitious one and the conception 
is not without its attractiveness. In the present state of our knowledge, 
however, it appears to many that the plan is possibly premature and that 
there is a great element of unreality in the results. It is only fair to the 
editors to say that they fully realise the difficulties of carrying out a survey 
of this extent on a uniform basis, and admit that the results are imperfect 
and will require to be modified in various ways. It seems fairly clear, 
however, that the difficulties of making such a map have been seriously 
underrated. Few workers in Europe have any extensive knowledge of 
soils outside their own countries, with the inevitable confusion as regards 
classification and nomenclature. At home, our soil workers have to be 
content with spending a few weeks in the field each summer. It is evident, 
therefore, that the difficulties are great and that the rate of progress must 
be slow. At the same time, the meetings of workers from different 
countries at the International Soil Conferences with the resultant exchange 
of ideas and experiences must be valuable in the development of the subject. 
Turning next to the methods employed in surveying, the profile is 
studied as regards horizons, colour and texture changes, structure, drain- 
age and vegetation. The surface horizons are naturally more extensively 
studied. As regards the chemistry of the profile, most weight is placed 
on the ratio of silica to sesquioxides ; other factors examined are the 
presence and accumulation of salts, including calcium carbonate, and 
changes in acidity with depth. On the results of these observations, the 
soil is placed in its appropriate class. In passing, it may be noted that 
there appears to be a certain reluctance on the part of the advocates of 
these methods to ascertain by means of carefully conducted field experi- 
ments whether some of the differences they are mapping are really signifi- 
cant in practice and whether some of the finer differences which they 
map, between soils within the same type, have any reality and make any 
appreciable difference in agricultural practice. 
As regards the utility of soil surveys generally, a reasonable case can 
be made out for the benefits which are likely to follow a careful survey of 
a new country which is just being developed. ‘The difficulty there, is to 
