GENERAL MEETING. 23 
A re-examination was then made of all the photographic appara- 
tus, and about 10 minutes after the second contact the principal 
photographic work was commenced; and this was continued with 
slight interruption until about 10 minutes before third contact ; 
150 dry plates and 30 wet ones being exposed. One of the inter- 
ruptions was for the purpose of making measurements of the 
diameter of Venus, which was done with a double-image micrometer 
attached to the 5-inch telescope. ; 
On going to the telescope to observe the last contacts, I found the 
limbs of Venus and the sun as steady as in the morning, and though 
there was now some haze over the sun it did no harm. The third 
contact was observed with great accuracy, nothing occurring to 
obstruct or complicate the very simple and definite phenomena, 
which were in the reverse order of those seen at second contact. 
The rim of light appeared around Venus as soon as the limb was 
visible beyond the sun, and was seen for nearly 10 minutes. The 
complete outline of Venus was visible for 2 minutes longer. No 
phenomena worthy of note were seen between third and fourth con- 
tacts. The lapping of the limb of Venus over that of the sun 
gradually but steadily decreased until the final separation, which 
was observed with great accuracy for such a phenomenon. Soon 
after the last contact the entire apparatus was again carefully 
examined and the necessary observations made to determine the 
errors of the chronometers. 
In the observations of interior contacts there was no trace of any 
tremor or fluctuation of the light in the cusps as they closed around 
the limb of Venus; and it is almost needless to say that there was 
no trace of a shadow or a black drop or ligament between the 
limbs at second and third contacts. The probable error for the 
second and third contacts was estimated at 0”.3; for fourth con- 
tact, 0’.5. 
Observers of transits of Venus and Mercury have written so 
much in regard to the obstacles encountered from the apparition of 
the shadow, or black drop, between the limbs of the two bodies at 
second and third contacts, and so full has been the testimony in 
favor of the existence and the almost necessary occurrence of this 
phenomenon, that at the transit of Mercury, in 1878, many ob- 
servers claimed, as evidence of their skill, that they did see it; 
while others, less fortunate, apologized for not seeing it. Observers 
of the black drop were so generally confined to those with imperfect 
