1895.] on the Badiant Heat from ilie Moon during an Eclipse. 627 



to 1 hr. 55 min. sidereal time, or 45 minutes after the last contact 

 ■with the penumbra. The values, however, up to 21 hr. 11 min. were 

 obtained through a moderately dense covering of clouds, and being 

 therefore of no value for our purpose, have been omitted from the 

 slide (6). It will be seen that the heat (observed) varies pretty 

 nearly as the light (calculated), a slight delay or lag being apparent 

 in fthe heat ; but the most remarkable fact that came out was that the 

 heat rapidly increased after the termination of the total phase, not 

 towards its usual value for Full Moon, but towards a value some 

 87 per cent, only of that amount, and though the observations were 

 continued half an hour after the last contact with the penumbra, there 

 appeared no disposition to a return to the standard Full Moon value. 

 This value was deduced from observations on October 3, 5, 6, and 

 November 2, 28, 30. 



Fig. 6. 



During the period of totality the observations were not reliable 

 owing to the feebleness of the Moon's image, which made it uncertain 

 whether or not it was properly upon the apparatus ; but those made 

 just before and just after totality indicate very little radiant heat. 



The next opportunity — an exceptionally favourable one — occurred 

 on January 28, 1888.* The sky was not obscured at all during the 

 whole progress of the eclipse, and the same apparent anomaly of the 

 heat not returning to its standard value, even as long as 1 hr. 40 min. 

 after the last contact with the penumbra was observed. But in 

 addition it was found that the radiation, which we began to measure 

 1 hr. 5 min. before the first contact with the penumbra, seemed to 

 begin to decrease almost immediately, so that when the time of 

 " First contact with the penumbra " had arrived, the heat had been 



* See also Trans, Koy. Dab. Soc, vol. iv., Series II., 1895, pp. 481-512. 



