396 



SCIENTIFIC RECORD FOR 1883. 



report will contain the work of all ten parties on a uniform plan. The 

 Commission's report states that, on the day of the last transit, the sky 

 was perfectly clear at about half the stations, while at the remainder 

 clouds impeded the work more or less, but nowhere to the extent of 

 producing failure. The number of photographic plates obtained at all 

 the stations, and which will be available for measurement, are in the 

 aggregate nearly fourteen hundred, of which about eight hundred were 

 obtained in the northern hemisphere and six hundred in the southern. 

 They are distributed with a fair evenness among the ten stations, ex- 

 cept that Auckland and Washington were unfortunate in obtaining very 

 few. The reductions of all these photographic observations are now 

 going on, four computers being employed in the work. The photo- 

 graphs obtained at three of the stations have already been measured, 

 and some progress has been made in the reductions based upon these 

 measurements. It is believed that the sun's distance derivable from 

 the transit of Venus in 1874 and 1882 must depend chiefly upon the 

 photographs; and when it is remembered that the conditions of 

 weather on the former occasion were so unfavorable as to allow only 

 between two and three hundred available negatives to be made in both 

 hemispheres, the remarkable success of the operations during the transit 

 of December, 1882, will be apparent. If no unforeseen delay occurs, 

 probably the definitive result from the photographs of both these tran- 

 sits of Venus can be arrived at in about four years. 



Transit of Venus, 1882. — A list of the photographic plates of the Transit 

 of Venus of 1882 in the hands of the Transit of Venus Commission for 

 discussion is given below, together with a list of contact observations: 



