330 



PROCEEDINGS OF THE AMERICAN ACADEMY 



posing the temperature of the standard has not been greater than 

 25° C. = 77° F. during the preceding six months. The boiling point 

 is determined from the temperature of the steam of pure water at a 

 barometric pressure of 760 mm. = 29.922 in. (reduced to 0° C.) at 

 the level of the sea and in the latitude of 45°, This standard coincides 

 with the perfect gas thermometer within 0°.l F. for temperatures be- 

 tween zero and 212° F. 



'LEONARD WALDO, 



Astronomer in Charge. 



" New Haven, Conn., March-October, 1882. 



■Yale Observatory Standard No. 61. — O. T. S., Observer. 



" 1. The first column gives the scale readings on the thermometer. 



" 2. The second column gives the sum of all the corrections to be 

 applied at the points of the scale indicated in 1, to reduce the readings 

 to the standard of this Observatory. 



'• 3. The third column gives the depression of the zero point caused 

 by heating the standard to 100° C. 



