130 Observations on the Annular Solar Eclipse 



The chief object to which I had proposed to direct my atten^ 

 tion, and observations, was the effect which the progress of 

 the eclipse produced on the thermometer, not only in the shade, 

 but likewise when subject to the influence of the solar rays. 

 .With this view four thermometers were carefully compared with 

 each other, that the observations might be reduced to one stan- 

 dax'd. One of these instruments was placed in the shade, sub- 

 ject to the aspect of a northern sky, and so placed as to be under 

 no influence of local radiation, being solely affected by the aerial 

 temperature ; — whilst another was suspended also in a free cir- 

 culation of air, but at the same time in the solar rays. 



The other two instruments were subject to experiment under 

 the direct influence of the solar heat, being enclosed in a box 

 having a glass cover, to insure protection from aerial currents. 

 The bulb of one was enveloped with a covering of black silk, 

 with the intention of increasing the range of that instrument, 

 and thereby more correctly detecting the loss, as well as increase 

 of heat during the progress of the eclipse. These instruments 

 were invariably kept directed to the sun. 



These being prepared, and the sun clear, the observations 

 were commenced, and continued at intervals as noted in the fol- 

 lowing table. 



