626 



The Earl of Bosse 



[May 31, 



for this purpose, and I find that I am reported to have said in that 

 lecture : " The eclipse was a very partial one, only about Jq- of the 

 Moon's diameter being in shadow ; but although this circumstance, 

 coupled with the uncertain state of the sky, rendered the observation 

 less satisfactory than it would otherwise have been, yet it was suffi- 

 cient to show that the decline of light and heat as the penumbra came 

 over the lunar surface, and their increase after the middle of the 

 eclipse, were sensibly proportional." This eclipse occurred on 

 November 14, 1872. On May 22, 1872, clouds had prevented obser- 

 vations during the whole progress of the eclipse. 



Fig. 5. 



On August 23, 1877, some determinations of heat during the total 

 eclipse were made. Clouds again interfered, and the observations 

 were very unsatisfactory, but after considerable delay they were 

 published in ' Copernicus,' vol. i. p. 22. 



No further opportunity occurred until October 4, 1884,* when, 

 during my absence in America, my astronomical assistant, Dr. Boed- 

 dicker, had the good fortune to get a far more satisfactory series of de- 

 terminations than any previously obtained. The observations were 

 carried on with as little interruption as possible from 20 hr. 27 min. 

 sidereal time, or 11 minutes before the first contact with the shadow, 



See also Trans. Boy. Dub. Soc, vol. iii., Series II., 1885, pp. 321-332. 



