304 



REPORT 1864). 



enable us to speak -witli confideuce ; the results are that the temperatures of 

 the dew-point, as found by the use of the dry- and wet-bulb thermometers 

 and my Hygrometrical Tables, are worthy of full confidence up to this 

 point. At heights exceeding 7000 feet, the three years' experiences do not 

 yield a sufficient number of experiments to give satisfactory results. Before 

 we can speak with certainty _at these elevations more experiments must 

 be made. 



Table XI. — Simultaneous readings of a deHeate blackened bulb thermometer 

 fully exposed to the smi's rays, and of a delicate thermometer carefully 

 shaded from the influence of the sun, the bulbs of the two instruments 

 being within 3 inches of eacli other, together with observations by 

 Herschel's actinometer, at different elevations. 



August 31, 1863. 



September 29, 1863. 



