CHAP, vii.j Spots in the Sun. 287 



pied a large portion of my father's attention. The present 

 is an admirable opportunity for studying these things, as 

 the sun is infested now with spots to a greater degree than 

 ever I knew it, and they are arranged over its surface in a 

 manner singularly interesting and instructive. The sky 

 here is so pure and clear in our summer that it would be 

 a shame to neglect such an opportunity of making experi- 

 ments on heat, and accordingly I have been occupied in 

 the December solstice in determining the constant of solar 

 radiation, that is to say, the absolute quantity of heat sent 

 down to the earth's surface from the sun at noon, or at a 

 vertical incidence. 



I do not think I have ever mentioned to you a remark- 

 able and splendid instance of liberality on the part of His 

 Grace of Northumberland, who has taken upon himself to 

 defray the expenses of publishing my observations at the 

 Cape, and that in a manner the most delicate and consi- 

 derate imaginable. In consequence " my book " will appear, 

 when it does appear, under his auspices, and I hope it will 

 not do discredit to his munificence. This is not the only, 

 nor the most remarkable, instance however, of his attach- 

 ment to the cause of science, and his disposition to pro- 

 mote and support it. 



MISS HERSCHEL TO SIR J. F. W. HERSCHEL. 



March 30, 1837. 

 ***** 



.... I have for the last five months been in con- 

 tinued fear of losing Mrs. Beckedorff (to whom I could 

 confide all my grievances). She is worn out with a cough 

 and breaking up of constitution, and we but seldom can 

 come together, which is when I am able to cross the street 



to go to her I experience a daily increase of pain 



and feebleness, so that I am (at least during this severe 



