44 



KAARF. MÜNSTER STRØM. M.-N. Kl. 



of a larger (lislrict, an investigation loi- wlii( li \f)rv\'ay would be better 

 qualilied than an}- otii< r l^iiropean cf)iintry, far more systematic investigations 

 ha\'(' to be carried out. 



'ilie best plan for such an investigation would be to select a number 

 of lakes (preferably not less than 50 to 100) subjected to as different condi- 

 tions as possible: in our Lowlands and Highlands, the Eastern and Western 

 districts of the Country, as well as in Trondelag, Nordland and P'inmark. 

 These lakes would then have to be examined at regular intervals (of a 

 fortnight) throughout the whole year or only in the summer, as the condi- 

 tons may be. This would have to be done b}- a person resident in the 

 various places in question to whom the necessary apparatuses could be 

 entrusted, and observations of the surface temperature (' 10^ C of accurracy) 

 would also be necessary; these persons would assumably not be qualified 

 for many investigations beyond the aforesaid. 



Chemical examination of the water in the lakes, would also be of great 

 use and might throw a light upon many of the problems within the plankton 

 range of science although it might be connected with practical difficulties. 



Christiania, the Botanic Museum of the 

 Royal Fredericks University, 

 October 30th, ig20. 



