I 



PREFACE. 



I 



Tx the accompanying treatise we have endeavoured to give the general results of our observations on the Hydrography and Pelagic 

 -L Life of tlie Northern Ocean, obtained, of late years, during our Marine-Biological investigations. More detailed results of our 

 observations in Norwegian waters, and the Herring Fishery carried on therein, we reserve for future publication. 



Materials for our treatise have also been obtained through the kind assistance of various public institutions and private 

 individuals, and the help thus afforded ns is specially alluded to in our work. 



A\ e desire to express our thanks to the Officers of the Eoyal Norwegian Navy, the Meteorological Institute, the Geographical 

 surveying Board, the Directors of the Bergen Museum, and to all those Shipowners and Masters of vessels who have accorded us their 

 valuable assistance. 



June 1898. 



Johan Hjort. 



H. H. Gran. 



