vi.] PROFESSORIAL LIFE. 123 



rations. I have, however, got a pupil to calculate my 



magnetic intensity observations. I have weighed and 



-uivd 800 individuals myself. I have had the 



mortification to discover that the construction of the 



dynamometer was extremely insufficient, but this can 



ely affect the relative results. I have separated the 



Ji.sh, Scotch, and Irish. The ages are chiefly from 



to twenty-four. 



'On the 15th the solar eclipse was most admirably 



seen here. ... I observed with a 7-feet reflector the 



immersion and emersion of the spots, of which tin 're 



sev.-rul, but I could not observe the slightest 



>rtion produced by refraction upon those delicate 



<ts. My attention was chiefly directed to this object : 



to examine the light from the sun's edges, at and near 



the annular period, in order to ascertain whether the 



dark lines in the spectrum were more numerous or 



nger in the light which must have traversed the 



greatest thickness of the sun's atmosphere, and which 



have been supposed by Sir D. Brewster and others to be 



due to the absorptive action of that atmosphere. An 



animation assures me that no material differ- 



cnnld rxist : indeed, J did not perceive the slightest. 



I then f.>; ,. < . .nr]ude that the sun's light is originally 



>-nt in those rays.' 



To the REV. DR. WHEWELL. 



EDiNm-H;ii, May 20th, 1836. 



' . . . One interesting point which seems to me to 



<!' development ie this the variation in the kind 



and (juantity <>f proof required as demonstration by the 



human mind in diH'en-nt ages. That the educated part 



.lankind aiv more acute than they were a century 



ago .rohahli'. Paradoxes cannot be so successfully 



now as they \\viv then ; ;in<! people are 



1 to t;ike up the ((Uerulous and futile olj < - 



t inns which passed current l.~>n -40, and which < L- 



i condescended to an-w.-r. Some parts of Newton's 



