TWENTY-FOURTH ANNUAL REPORT 141 



Harbor Water — T eynperature and Specific Gravity 



Temperature. Specific Gravity, 



January 43- 1.012 



February 41° 1.014 



March 43° 1.011 



April 45° 1.009 



May 51° 1.011 



June 60° 1.012 



July 67° 1.014 



August 68° 1.014 



- September 68° 1.013 



October 64° 1.013 



November 57° 1.011 



December 46° 1.012 



Accessories. — In making shipments of fishes by train or 

 otherwise, where a steam-driven air compressor is not available, 

 the use of a hand air pump saves much labor. An air pump of 

 the kind shown in the accompanying photograph has been added 

 to the collecting equipment of the Aquarium. With branch pipes 

 of rubber led to each tank, the work of aerating the water is 

 simplified and made more effective. The end of each branch pipe 

 is plugged with porous wood which liberates the air as a fine mist 

 and not in large and ineffective bubbles. 



All exhibition tanks in an aquarium must be supplied with 

 strainers of some sort in their top overflows and bottom drains, 

 to prevent the escape of small fishes and the clogging of waste 

 pipes with various substances. In salt water tanks where metal 

 and wire strainers rust out quickly, their renewal involves consid- 

 erable expense, while their rusting serves to discolor the supply 

 of stored sea water. The use of strainers made of lead or rattan 

 has obviated these troubles. Several types are shown in the ac- 

 companying photograph. 



Appropriation. — The appropriation for the year 1919 was 

 reduced to the legal minimum of $45,000. The appropriation for 

 the ensuing year has been fixed at $54,891.30, but the increase 

 will necessarily be devoted to the advancement of wages, and the 

 Aquarium will probably be unable to make a number of needed 

 repairs. 



Respectfully submitted, 



Charles Haskins Townsend, Director. 



