INTRODUCTION. 



xv 



Dr. Wiillner, Professor ot Physics, Aachen. 



Dr. Zeuner, Director ot the Polytechnic School, Dresden. 



Dr. Zetzsche, Director of the Polytechnic School, Chemnitz. 



ITALY. 



II Com. Blaserna, Professor of Physics and Rector of the Royal University of 



Rome. 



II Com. Cantoni, Professor of Physics at the Royal University of Pavia. 

 II Cav. Respighi, Professor of Astronomy in the Royal University of Rome, 



and Director of the Observatory of the Campidoglio. 



THE NETHERLANDS. 



Professor Dr. P. L. Rijke, Conseiller d'Etat (President). 



Professor Dr. H. G. de Sande Bakhuyzen. 



Professor Dr. C. H. D. Buys Ballot. 



Professor Dr. J. Bosscha. 



Professor Dr. F. C. Donders, F.R.S., President of the Royal Academy of 



Science, Amsterdam. 

 Professor Dr. J. W. Gunning. 

 Professor Dr. R. A. Mees. 

 Professor Dr. V. S. M. Van der Willigen. 

 Dr. D. de Loos, Director of the Secondary Town-School ofLeyden (Secretary). 



NORWAY. 



Professor Esmark. 



Herr Mohn, Director of the Meteorological Institute of Norway. 



Professor Waage. 



RUSSIA. 



M. Struve, Conseiller Prive Directeur 



de 1'Observatoire Central Nicolas 



(President). 

 M. Ovsiannikow, membre de PAca- 



dernie. 



M. Gadolin, membre de 1' Academic. 

 M. Gruber, Professeur de P Academic 



de Medecine et de Chirurgerie. 

 :\I. Stubendorf, Colonel d'Etat-Major. 



M. Wyschnegradsky, Professeur de 



1'Institut technologique. 

 M. Beilstein, Professeur de PInstitut 



technologique. 

 M. Barbot de Marny, Professeur de 



PInstitut des Mines. 

 M. Koulibine, Professeur de PInstitut 



des Mines. 



SWITZERLAND. 



Professor E. Wartmann (President). 

 Professor J. Amsler Laffon, 

 Professor D. Colladon-Ador. 

 Professor Dr. F. A. Forel. 

 Professor Dr. E. Hagenbach-BischofF. 



Professor Ad. Hirsch. 

 Professor Albert Mousson. 

 M. E. Sarasin-Diodati. 

 Professor L. Soret. 

 Colonel Gautier (Secretary). 



