314 The Past and Coming Transits and Arctic Explorations. 



and a new cause of regret added to several which will be recognized by 

 those who come after us, as they scan the history of the late transit. 



But in 1882 this method— the mid-transit photographic method — 

 will be the one on which, I venture to predict, chief reliance will be 

 placed. Owing to the long duration of that transit (exceeding, by two 

 hours, the duration of the recent transit,) it will be impossible to find 

 any pairs of stations, northern and southern, at each of which the whole 

 transit will be favorable seen. * * * So far, then, as the older methods 

 of observing transits are concerned, the transit of 1882 can only be 

 observed by Delisle's method. But we have seen that contact obser- 

 vations can not be relied upon for improving our knowledge of the sun's 

 distance. And if they could not be relied upon for that purpose now, 

 astronomers will have secured valuable determinations of the sun's 

 distance from observations of the planet Mars, during the singularly 

 favorable opposition of 1877.-^' 



But mid-transit can be advantageously recorded by photographic 

 appliances in 1882, if only suitable soutliern stations can be occuj^ied 

 for the purpose ; and as no other method is available, except the demons- 

 trably untrustworthy Deli^lean method, we can scarcely doubt that an 

 effo.i't will be made by the scientific nations to overcome the difficultiea 

 which will be certainly present themselves in the search for and 

 occupation of stations in the soiithei'n hemisphere. * * 



And there will be this further difiiculty in 1882. On the occasion 

 of the late transit the. Americans, finding that no part of the transit 

 would be visible from their own territory, appear to have considered 

 it their natural and obvious duty to occupy stations in Siberia, Jajoan, 

 the Sub-Antarctic ocean, and other places, where we in England were 

 assured that no stations would be, and that no stations coidd be occupied. 

 But in 1882 the whole transit being most favourably observable from 

 the whole part of the United States, it seems not unlikely that our 

 Transatlantic cousins will consider it their part to keep their astron- 

 omers at home, leaving to other nations the task of finding suitable 

 southern stations. I hesitate to say that this ivill be their view of the 

 matter, for it is difficult to reckon on considerations of that kind where 

 Americans are concerned. One might have thought, that after 

 observing the eclipse of 1869 at a hundred stations in the United 

 States, American astronomers would have been content to leave the 

 observations of the Mediterranean eclipse of 1870 to European 

 astronomers. But, in point of fact, they did nothing of the kind ; but, 

 with a perversity which can not be too strongly reprehended (at least 



* It may wel. be hoped that stellar photography, will be employed to obtain records of the 

 position of Mars among the stars on that occasion. This method seems to promise better 

 results than auy other yet applied, or at present available. 



