1868.] 



Total Eclipse of the Sun. 



89 



of course be two such planes, touching the two sides of the cone respec- 

 tively. Each of these will be projected on the visual sphere into a great 

 circle, a common tangent to the two small circles, which are the projections 

 of the suri and moon. In crossing either of these there will be a rapid, 

 chauge of illumination (feeble though it be at best) which will be noticed. 

 According as the observer mentally regards darkness as the rule and illumi- 

 nation as the feature, or illumination as the rule and darkness as the feature, 

 he will describe what he sees as a beam or a shadow. The direction of these 

 beams or shadows given by theory, as just explained, agrees very well with 

 the drawing sent by Governor Hennessy, which does not represent the 

 left-hand beam so distinctly divided as it appears in the woodcut. 



The times mentioned in the above despatch have not been corrected for 

 the error of the chronometer-watch. In the following Tables, furnished by 

 Staff Commander Reed, the corrected mean times alone are printed. The 

 observations of time by ("apt. Reed, Mr. Ray, and Mr. Doorly were made 

 by Government pocket chronometer No. 1887, which was fast on mean 

 time of place h 4 m 8 s * 7 ; those by Mr. Ellis by a gold pocket watch, com- 

 pensation balance, which was fast on mean time of place h i/ m 2 s "7; 

 those belonging to the meteorological observations with a pocket watch, 

 which was fast on mean time of place h 2 m 4 7 s " 9. 



G. G. Stokes.] 



Meteorological Observations taken on board H. M.S. 'Rifleman' at Bar ram 

 Point, during the Total Eclipse of the Sun, August ISth, 1868. 



Mean time at 

 place. 



Marine baro- 

 meter in 

 Chart-house. 



Mean of 

 two ther- 

 mometers 

 in Chart- 

 house. 



Dry thermo- 

 meter hung in 

 the main rig- 

 ging exposed 

 to the sun. 



Wet thermo- 

 meter hung in 

 the main rig- 

 ging exposed 

 to the sun. 



A.M. h 



m 





in. 











7 



57 



121 



29-98 



81 











8 



57 



I2-I 



30*01 



81 



85 



92 



93'5 



9 



57 



I2'I 



30-00 



86-5 



83-5 



IO 



57 



121 



29-99 



84 



9 1 



87 



ii 



57 



I2'I 



29-98 



85 



88 



85 



P.M. 















O 



*3 



12*1 



29-96 



85 



9 1 



88 



o 



42 



I2"I 



29-96 



85 



90 



87 



o 



57 



12- I 



29-94 



85 



88 



86 



I 



12 



I2'I 



29*93 



85 



87 



85 





23 



9 -I 



29-92 



85 



85 



83 





32 



121 



29-92 



85 



85 



83 



I 



57 



I2"I 



29-91 



85 



9i 



85 



2 



27 



121 



29-91 



85 



96 



90 



2 



48 



151 



29-91 



86 



96 



89 











Jno. W. Eeed, 











Staff Commander in charge of China 



Sea Survey. 



