UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 8, No. 9, pp. 349-352 November 18, 1911 



ON AN IMPROVED FORM OF SELF-CLOSING 



WATER-BUCKET FOR PLANKTON 



INVESTIGATIONS 



BY 



CHAELES ATWOOD KOFOID 



(Contribution from the Laboratory of the Marine Biological Association of San Diego) 



An account of the water-bucket used in plankton investiga- 

 tions at the Biological Station at La Jolla, near San Diego, was 

 published by me (1905) several years ago. This bucket has been 

 used repeatedly in connection with various investigations (see 

 McEwen, 1909) in progress at the station, and has worked very 

 satisfactorily. Continued use and the accidents inevitable on 

 shipboard have developed certain defects in construction which 

 have been eliminated in a new model constructed for me by Mr. 

 V. Arntzen, expert mechanician of the University of California, 

 and placed in the exhibit of instruments for oceanographic 

 research in the Musee Oceanographique at Monaco, Principaute 

 de Monaco, founded by S. A. S. Albert I, Prince of Monaco (see 

 Kofoid, 1910). It is the purpose of this note to record these 

 improvements. 



In the first model the four standards (figs. A, B) connecting 

 the brass castings which form the head and base, were made of 

 heavy brass tubing 16 mm. in diameter. These proved too weak 

 to stand the usage in handling the heavy load of water, and also 

 gave trouble by slight dents which they received and which 

 interfered with the smooth working of the sleeves upon the 

 cylinder and lid that guide these parts to their seats in closure. 

 Accordingly in the new model solid rods of hard brass were 

 substituted. 



