JuLy 6, 1899] 
NATURE 
227 
frequency within wide limits. The wider the valve is 
open the larger is the current, and the lower is the 
frequency, and vice versd. With this apparatus in circuit 
with a 10-inch coil connected direct on to the 100-volt 
supply mains, it was found that by adjusting the valve the 
primary current could be altered from o to 25 amperes, 
while the pitch of the sound of the discharge could be 
changed from a very shrill whistle down to a rattling 
roar. By introducing additional self-induction into the 
circuit the frequency can be lowered still further. 
The direction of the current through the apparatus 
does not affect the results, and the arrangement, when 
suitably adjusted, works well with alternating current, 
the sparks in each direction being of equal power. The 
troublesome fatigue phenomena to which the Webnelt 
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instrument is liable appear to be absent, while the dif- 
ficulties as to the fusing of the platinum wire and the 
cracking of its insulating sheath are also avoided. This 
improved instrument has in fact all the advantages of 
that of Caldwell, of which it is a modification, with the 
further advantage of easy adjustment to suit different 
voltages, and to give different amounts of power and 
different frequencies. A. A. CAMPBELL SWINTON. 
THE SEVENTH INTERNATIONAL 
GEOGRAPHICAL CONGRESS, 
yA T the meeting of the sixth International Geographical 
Congress in London in 1895, it was decided that 
the seventh should take place in Berlin in 1899. The 
Berlin Geographical Society, according to the precedent 
of previous Congresses, undertook the necessary arrange- 
NO. 1549, VOL. 60] 
ments, and these have now been perfected. The 
Congress will differ from that of London by the absence 
of a geographical exhibition, and by the more thorough. 
organisation of scientific excursions under specialist 
leaders before and after the meeting. 
The proceedings will commence informally by an 
evening gathering on Wednesday, September 27, when 
an opportunity will be afforded for conversation amongst 
the members. Next day the formal opening of the 
Congress will take place in the splendid new buildings of 
the Prussian House of Representatives, which has been. 
generously placed at the disposal of the Congress for 
the whole meeting. As in London, the proceedings of 
each day will include a forenoon sitting for the discussion 
of papers of general interest, and several sectional meet- 
ings in the afternoon for subjects which appeal to a 
limited number of specialists. 
The Bureau of the Sixth Congress (of which Sir 
Clements Markham is President and Dy. Scott Keltie 
and Dr. H. R. Mill Honorary Secretaries) will present a 
report and resign its functions to that of the new 
Congress, the President of which is Baron von Richt- 
hofen and the Secretary Hauptmann Kollm. The various 
committees of the seventh Congress, honorary and 
executive, bear the names of the most distinguished 
geographers of all countries, and the gathering promises 
to be a really representative one. 
The papers which haye been promised are grouped 
into seven main divisions, viz. mathematical geography, 
physical geography, biogeography, anthropogeography,. 
exploration, historical geography, and geographical 
education. The papers will be very numerous, but as a 
strict time limit of twenty minutes is to be enforced, 
there will be an opportunity for effective discussion. 
Some of the most interesting subjects to be dealt with 
in the first group are the position of mean sea-level, the 
present state of research on the tides, and seismology, 
while in physical geography Prof. W. M. Davis and 
Prof. de Lapparent will deal with questions of geomor- 
phology, and oceanography will be treated in great detail 
in conjunction with polar research. 
Dr. Nansen, Sir John Murray, the Prince of Monaco,. 
Prof. Chun (of the Valdivia expedition), Profs. Pettersson, 
Thoulet, &c., have all promised to take part. The plans 
of the German Antarctic expedition will be explained by 
Dr. von Drygalski, the chosen leader ; while Sir Clements. 
Markham and Sir John Murray will give an account of 
the progress of the arrangements of the British Antarctic 
expedition. It is hoped that a general scheme may be 
agreed upon for simultaneous and strictly comparable 
observations, so that by combined action the two expedi- 
tions will secure the maximum result for their labours. 
The distribution of plants will be dealt with by Profs. 
Engler, Drude and others, while numerous papers on 
other branches of physical geography are promised. 
Under the head of “ Exploration,” the names of several 
Germans are announced, but no British subjects have 
come forward to claim international importance for their 
journeys. 
One feature of the Congress which promises a practica} 
outcome is the prominence which is given to questions 
of nomenclature. Prof. Richter (of Graz) will propose 
a systematic terminology for use in research on glaciers > 
and the terminology and nomenclature of the forms of 
the ocean floor will be discussed by Profs. Wagner, 
Kriimmel, Voiekoff, and Dr. H. R. Mill. Proposals for 
the uniform use of the metric system and the centigrade 
temperature scale in all geographical work will also 
be put forward. : 
The scientific excursions, which for the most part pre- 
cede the meeting of the Congress, have been wel? 
organised. The programme has just been issued, giving 
particulars as to route, leaders, terms, &c., and also con- 
taining a list of the best maps and guide-books, and a 
