1868.] Easy Method of measuring Intensity of Total Daylight. 525 



females, 138 have been found on both sides, 55 on the right side onlyy 

 and 69 on the left side only, making 124 single or one-sided specimens, 

 and giving rather fewer on the right and more on the left side than in the 

 males. In the females, also, it will be observed that the proportion of the 

 abnormalities found on both sides to those found on one side only in the 

 same sex, is much less than in the males. This is found to depend upon the 

 smaller number found in both arms of the female, viz. 96 in the females 

 to 125 in the males, while the number found in the left arm only of the 

 females is 51 compared with 38 in the males-, and that found in the right 

 arm only of the females is 29, compared with 36 in the males. On the 

 other hand, the number found in the left leg only in the female is but 1 0, 

 in comparison with 13 in that of the male, and with 20 in the right leg 

 only of the former sex. 



The disproportion in this particular comes out still more markedly when 

 the whole number of 102 subjects comprised in the Tables of the three 

 last years, viz. 68 males, and half that number, or 34 females, is taken into 

 consideration. 



The number of abnormalities in the 68 males is 414 on both sides, 108 

 on the right, and 101 on the left side only, making 209 one-sided speci- 

 mens. The number of abnormalities in the 34 females is 209 on both sides, 

 68 on the right, and 81 on the left side only, making 149 one'sided spe- 

 cimens. 



Thus in the females we find a proportionate preponderance to the 

 amount of about 45 one-sided specimens ; and these are mainly composed 

 of those on the left side only. 



The total number of abnorm.alities in the 102 subjects is 981, of which 

 623 are in the 68 males, and 358 in the 34 females. The number found 

 on both sides is 623, of which 414 are in the males and 209 in the females. 

 The number found in the right side only is 176, of which 108 are in the 

 males and 68 in the females. The number found on the left side only is 

 182, of which 101 are in the males and 81 in the females, making a total 

 of 358 one-sided specimens. 



XVIII. " On an Easy Method of measuring approximately the In- 

 tensity of Total Daylight.-" By Roger J. Wright, Esq. Com- 

 municated by Professor Stokes, Sec. R.S. Received May 21, 

 1868. 



An easy method by which the amount of light may be at any time mea- 

 sured and registered appears to be still wanting. I would suggest the 

 following plan, by which I believe the desired object may be attained. 



A B is a rod of solid metal, terminated by a heavy base, which keeps the 

 rod in a perpendicular position. C D is a hollow tube, blackened inside, of 

 such a diameter as exactly to fit and slide over A B. The extremity, B, of 

 the rod A B is painted of a snowy white, with a jet-black spot in the centre, 



