292 TRANSIT OF VENUS, 1874. EGYPT. 



The last cloud remained so long that I was afraid to leave the micrometer in 

 the telescope any longer, so I changed it for the negative eye-piece (212). 

 When the cloud opened I saw Venus very close to the limb, but no sort of 

 shadow of contact as yet. The shadow then began to appear, and I tried to 

 note the instant, but feared to interrupt my wife counting so near contact. 

 I tried to note some one instant, but could not, the shadow came so gradually. 

 The Sun becoming brighter, I saw a modified short ligament form, but did 

 not see the edges form into sharp curves and creep apart, as sometimes with 

 the model. Blackness gathered gradually, and at last came an instant when 

 it seemed to be as black as the planet, and to have no light crossing it. This 

 was at 13 b . 22 m . 25 s . by the clock. As I continued to watch the ligament 

 (not moving my eye from the telescope), the Sun became suddenly brighter, 

 and I saw a sort of parting of the ligament by a very narrow white line, 

 which either became definite, or I perceived it to be definite, as the egress 

 went on. This appearance is represented in Figure 1, Plate X., but I cannot 

 draw the white line fine enough. The white line clung to the planet's edge, 

 and at last the planet was projecting beyond the Sun's limb, with the thread 

 of light clearly biting into the sky. (Figure 2, Plate X.) 



I account for having seen the internal contact apparently completed by the 

 fact that there yet remained a film of cloud over the Sun, of which I was 

 made aware by the Sun becoming brighter just as the line appeared. I 

 watched this appearance until 13 h . 24 m . 25 s . by the clock, when I concluded 

 that the white line was not of a passing character, but was due to atmosphere 

 or some other cause. Feeling disappointed at having, in consequence, lost 

 two of the most valuable minutes, I replaced the micrometer and took the 

 following measures of the distance between the cusps and of the diameter of 

 Venus, in the direction parallel to the line of cusps, the latter being continued 

 until the planet was half emerged : 



MlCROMETEE READINGS for DISTANCE of CuSPS. 



Time by Dent 2009. Micrometer Headings. 



h m 



. 25. 5g 26-249 



26.26 25'40I 



26. 5o 25'43g 



27. 10 25'63o 

 27.35 25-802 



Time by Dent 2009. Micrometer Readings. 



h m 



i3.27.53 25-g3o 



28. 1 8 26-021 

 28.44 26-104 



29. 5 26-145 

 29. 23 26-258 



