Oct. 22, 1885] 
the data on which the geological boundaries have been 
traced, and can thus judge where and how far these are 
conjectural. Weare not aware of any other published 
maps where this confession has been so frankly made. 
The pale yellows and greys adopted for the superficial 
deposits cover so much of each sheet as to show at once 
how large a part of the ground is occupied by them. The 
detrital material is traced up to its source upon the table- 
lands, and being of poor agricultural value its colour on 
the map shows where farming operations are least likely 
to be successful. Where observations by boring or 
otherwise have been made on the nature of the soil and 
subsoil these are marked on the spot by the requisite sign, 
and as the borings are numerous these indications abound 
all over the map. 
During the progress of the work improvements have 
been’ made in the methods of surveying and also in the 
modes of expressing geological details on the maps. In 
the Brussels area, for example, besides the ordinary 
borings into the soil and subsoil, deeper borings have 
been made to ascertain the nature and succession of the 
strata underlying the uppermost deposits. Messrs. Rutot 
and Van den Broeck, two of the staff, have invented an 
ingenious instrument with which they can ascertain the 
nature of the formations down to a depth of even Io 
metres. By its means they have pierced below the sub- 
soil in all directions, and have accurately traced out the 
areas of the younger deposits around Brussels. The 
results obtained by them at each boring are clearly en- 
graved on the map; so that at numerous points all over 
the district the farmer, the water-engineer, the railway- 
contractor, the quarryman, and others can learn precisely 
through what layers they must pass in any cutting or 
excavation beneath the surface. By another ingenious 
device, the section of each artesian well at Brussels is 
represented on the map beside the position of the well, 
and so clearly that the succession of rocks bored through 
may be taken in by the eye at once. 
Each sheet of this detailed survey is so crowded with 
information that to those who have been accustomed only 
to the ordinary style of geological map-making it may at 
first seem a little confused. But if any one will take the 
least trouble he will soon find that the confusion is only 
in appearance. No maps have yet been published in any 
country giving so large an amount of accurate information 
with such clearness and precision, and where the actual 
facts are kept so clearly apart from inference. These sheets 
are not wall-maps to be looked at from a distance, but 
detailed maps to be closely studied in the hand. And 
they will well repay an attentive study. There is probably 
no national Geological Survey in any part of the world 
which may not find in them some useful hint or suggestion 
for its own improvement. 
On completion of the detailed survey it is part of the 
original plan to prepare a smaller or wall-map like that of 
Dumont. But such a map is hardly needed ; at least its 
preparation can well stand over until the whole country 
has been surveyed in detail by the methods so well con- 
ceived by M. Dupont. But besides the maps, the work 
of the Belgian Survey has included the preparation of 
ample explanations illustrative of the maps. Each sheet 
is intended to be accompanied with an “ Explication” 
giving the detailed structure of the ground, descriptions 
of the rocks, natural sections, lists of fossils, and all the 
information required as supplementary to the geological 
maps. A number of these memoirs have already been 
printed. Each of them contains fundamentally three 
sections running N. and S. across the formations, which 
in Belgium have a general E. and W. strike. These 
sections are described in detail, and full local references 
are given. The books are well printed, and the coloured 
plates of sections are excellent, while a novel attraction is 
given by the insertion into the text of coloured engraved 
sections of special localities. 
NATURE 
599 
None of the maps or explanations, though they have 
been ready for some time, have yet been published. They 
are to be seen, however, in some of the public libraries 
and museums in Europe. Belgium has every reason to 
be proud of them, and we trust that the delay in their 
publication will speedily be followed by the issue of the 
whole series now ready and by the completion of those in 
progress. It is impossible to over-estimate the practical 
utility of such a detailed survey in a country hke Belgium. 
No time should be lost in pushing on and bringing to a 
conclusion a work which has been so admirably begun. 
ARCH, GEIKIE 
THE THIRD INTERNATIONAL GEOLOGICAL 
CONGRESS 
HE third International Congress of Geologists, 
postponed last year on account of the spread 
of cholera in southern Europe, has just been held 
at Berlin. Each successive gathering has far surpassed 
its predecessors in numbers and in the representative 
character of its members, the numbers attending the 
meeting at Berlin being no fewer than 255. Of these of 
course the large majority were Germans, who mustered 
in all 163. Italy, however, furnished 18 representatives ; 
Austria, 16; Great Britain, 11; France, 10; United 
States, 9; Belgium and Russia, 6 each; Sweden and 
Switzerland, 3 each; Norway and Holland, 2 each; 
Spain, 1; Brazil,1; India, 1; Japan, 1; Portugal, 1; 
Roumania, 1. The meetings were held in the buildings 
of the Reichsrath, or Parliament, the large room set apart 
for the deliberations of the Congress being that of the 
Lower House of Representatives, and no little interest 
was taken by the foreign geologists in the names of the 
Members of Parliament inscribed on the backs of the 
seats. The door also was pointed out from which the 
great Chancellor emerges to launch his philippics against 
the contumacious opposition. But the gevzs /oc’ inspired 
no flights of eloguence nor much disputatiousness among 
the geologists. The use of French as the language of 
discussion was no doubt one effective cause of silence on 
the part of many members who would otherwise only too 
readily have made themselves heard. Under such 
circumstances the Latin races have of course a consider- 
able advantage over the Teutonic. One of the Berlin 
papers gave articulate expression to the complaint that 
in an audience nearly two-thirds of which were Germans, 
French should have been chosen, and great was the 
delight expressed by the German element in the Congress, 
when the Minister of Public Instruction, who officially 
welcomed the assembly, gave his eloquent and appro- 
priate address in German. But by common consent, and 
j with much good humour, though often with a disregard 
for the claims ef grammar, idiom, and pronunciation that 
must have been infinitely ludicrous to the French-speaking 
members, the international official language was used 
throughout the proceedings. 
The ostensible work of the Congress, which lasted 
nearly a week, may be divided into five parts. Of these 
the first in order of treatment and also of importance was 
the report of the Commission entrusted at the previous 
(Bologna) meeting with the preparation of a geological 
map of Europe. During the four years that have elapsed 
since the Congress determined to undertake this work, 
satisfactory progress with it has been made, The topo- 
graphical outlines of the map have been completed and 
engraved, and the Commission were able to show upon the 
wall a mounted copy of the outline map. The materials 
necessary for filling in the geology have already been — 
supplied for a large part of Europe, and it is expected 
that in the course of next year the work will be so far 
advanced that proofs in colour of many of the sheets of 
the map will be ready. There can be no doubt that the 
preparation of this great map is the most important and 
