21 



mentioned for the determination of both the oxygen and the 

 carbon dioxide. This involves the collection and shipment of 

 eight bottles of water from each of the three stations — a total 

 of about nine hundred and fifty samples being shipped in 1897 

 and 1898. The water was collected with the plankton pump 

 by means of a small pet cock inserted in the discharge pipe. 

 A rubber tube is fastened upon this and inserted in the Ijottle 

 and water suliicient to fill the bottle three times is pumped 

 through it. The bottle is then closed, the sample being col- 

 lected with a minimum contact with "the air. If the change 

 in the water between the time of collection and the time of 

 analysis does not vitiate the results, we shall find the^e gas 

 determinations of great importance in the discussion of the 

 plankton data. 



The equipment has been maintained in first-class condition 

 so far as the wear and tear of property subject to the vicissi- 

 tudes of an aquatic environment will permit. The hull of the 

 laboratory boat has been provided with salt shelves and its 

 bottom thoroughly salted to insure its preservation. The decks 

 and guards have been painted repeatedly, and the canvas roof 

 has received a heavy coat of paint. The floors have also been 

 treated with several coats of oil. Three years' experience in 

 our floating laboratory has only increased our satisfaction with 

 its fitness and convenience for the work of a biological station. 



The steam launch, with the new equipment of machinery 

 described in the last report, has been of great service. A few 

 repairs have been made from time to time upon the engine, and 

 the boiler and stack have been provided with a shield to decrease 

 heat in the launch. New tubes have also been placed in the 

 boiler. In 1897 the steamer " Josie Sivley" collided with the 

 "Illini" while she was at anchor on the river front, and crush- 

 ing her against the guard of the laboratory boat opened a seam 

 upon the ]arl)oard side and broke several ribs and a stanchion. 

 The launch sunk in shoal water and was easily raised, the 

 damage being subsequently thoroughly repaired. In the spring 

 of 1897 Mr. Newberry secured an engineer's license, and has 

 since cared for the launch. 



During the session of the Summer Scliodl the carrying 

 capacity of the launch is severely taxed in providing transit for 



