ERRATA IN VOL. XI. 



Page 415, Hue 10 ; insert 1^ in blank space. 

 — 432, — 9, for O x : C read C : C 

 18, for C x : C read G 1 

 C x : C read C, 

 - 26, for C x : C read C, 

 — — 28, for : : read C, 



ERRATA IN VOL. XII. 



Page 189, art. 4, line 2, for xf read x a 



• „ „ „ 4, for tz read ta 



Page 192, art. 17, line 4, <?e/e the initial " 3 " 



„ 195, art. 29, line 4, for (1+tf 3 ) read (1-hz 3 ) 2 

 Pages 189, 192. 196, arts 1, 15, 86, for vol. xiii. read vol. xii. [The 

 XIII, at foot of No. 170 of the Proc. L. M. S. is wrong.] 



Page 301. In the title of Mr. A. Gray's letter, for "Number of Elec- 

 trostatic Units in the Electromagnetic Unit of Electromotive 

 Force," read " Number of Electromagnetic Units in the Electro- 

 static Unit of Electromotive Force." 



Page 304, lines 9 to 13. In the values of R tan a given in the quota- 

 tion from Mr. Shida's report, insert the factor 10 9 . 

 Page 335, line 9 from bottom, for Plate XI. read Plate IX. 

 Page 348, lines 32, 40, and 43, for dimension read dimensions. 



