XXVI. TEEE TEMPERATURES. 



Recorded by Roy W. Squires. 



During a period lasting from January 15, to June 3, 1894, 

 Mr. Squires made continuous observations on the temperature 

 of a trunk of the Box- elder (Acer negundo) and the surround- 

 ing air. Owing to the press of other duties he has been unable 

 to prepare the results for publication, and the detailed record 

 is presented below with a scanty comment wholly incommen- 

 surate with the importance of the work. 



The data obtained were desirable as testing the current con- 

 clusions concerning the influence of the different factors in the 

 determination of the relative temperatures of massive organs 

 and the air, as well as the changes in the absolute temperature 

 of the trunk itself. 



The period of observation included the season of long con- 

 tinued cold, the spring season, and the early part of the sum- 

 mer when the thermometer had reached nearly its maximum 

 limit. The locality is in 45° north latitude, and lies about equi- 

 distant from the January isotherms of 0°C. and -18°C. Rec- 

 ords were made three times daily during the entire period, 

 except in the few instances when the temperature fell below 

 the range of the instruments used. The tree upon which the 

 observations were made is a pistillate specimen about twenty 

 years old. The trunk and its branches reach a height of 

 ten meters. The trunk at breast height is 28cm. in diameter, 

 and at a distance of 2.5 meters from the ground is divided into 

 two main branches. The bark is dark brown in color and only 

 slightly roughened. The soil in which the tree is fixed is a gla- 

 cial sand through which run thin layers of clay and shale, and 

 is underlaid at some depth with limestone. The tree stands 

 midway between two dwelling houses, 14 meters apart north 

 and south of it; it is thus sheltered from the extreme violence 

 of storms while it receives the entire daily course of the sun. 

 The temperature of the air was read from an ordinary naked 



