Fig. 17. Nansen water bottles, rack and storage box, on quarter- 

 deck 



Fig. 18. A silk plankton net coming up after 

 being towed. Used to collect the microscopic 

 forms of life floating in the ocean 



Fig. 19. Seiwell at work in the chemical laboratory. Analyses 

 were made for many substances, like phosphates and oxygen, 

 which are concerned in the life of the plankton 



•Fig. 20. Parkinson testing the potential gradient 

 recorder. This instrument measures the po- 

 tential gradient of the atmosphere 



24 



