THE COMING TRANSIT OF VENUS. ■ 391 



part of Asia and on the islands of the Southern Pacific, and the expense of fitting 

 out expeditions to go to these distant places was large. Germany alone spent 

 $150,000 on her share of the work. This year the work will be far less expen- 

 sive because the transit can be seen from all the eastern part of North America 

 and from all of South America, so that it will not be necessary to send out as 

 many parties as in 1874. The observatories already in active operation in 

 this country, South America, Africa and Australia, can be utilized to their full 

 extent. And then the direct outlay will be less because the instruments prepared 

 for the last transit can be utilized for the coming one. 



England, France, Germany and the United States have already sent out 

 their expeditions. The English will occupy thirteen stations, viz : — ^Jamaica, 

 Barbados, Bermuda, Cape Colony (3), Madagascar, Natal, Mauritius, New Zea- 

 land, Brisbane, Melbourne and Sydney. France sends out six parties; to Guad- 

 elope or Martinique, Cuba, Florida, Coast of Mexico, Rio Negro and Santa Cruz. 

 Germany has chosen four stations; at Hartford, Conn., Aiken, S. C, Bahia 

 Blanca and Punta Arenas. 



Parties from the United States will be stationed at the following places : 

 Santa Cruz, Santiago, New Zealand, aud Cape of Good Hope. The principal 

 stations in this country will be Cedar Keys, Fla.; San Antonio, Texas; Fort 

 Thorn, N. M. 



The endeavor has been made to choose the places so that the observations to 

 be made may be the most useful in the final solution of the problem. At the 

 same time it has been necessary to take into account the meteorological condi- 

 tions of the several places and to so arrange the several stations that the probabil- 

 ity of unfavorable weather at all the places in any one region may be the least 

 possible. This was done at the International Conference on the approaching 

 transit of Venus held in Paris from the 5th to the 13th of October, 1881. It is 

 of course, necessary that the stations be widely separated from one another in 

 order that the two apparent paths of Venus across the Sun's face may be as far 

 apart as possible and render any small error in the observations as harmless as 

 may be. The work itself.is of extreme delicacy. Equal to that, for instance, in 

 the case where a surveyor would be required to find the exact distance of an ob- 

 ject six miles away, while not allowed to move his instruments more than three 

 feet in any direction. When such exact work as this is required, it is not strange 

 that particular attention should be paid to the selection of proper stations. 



There seems to be considerable difference of opinion among the four nations 

 as regards the best methods of observing the transits. There are three essential- 

 ly different ways of attacking the problem: i. By observation of the time of ex- 

 ternal and internal contacts at ingress and egress; 2. By making direct meas- 

 ures of the distance between the centre of Venus and the edge of the Sun; 3. 

 By photographing Venus and the Sun, and measuring their relative positions after- 

 ward. 



The English are the advocates of the first method, the Germans of the second, 

 and the Americans of the third. Although the method by contact is apparently 



