234 D. P. Todd—Search for a Trans-neptunian Planet. 
planet was more probably in one portion of the -heavens than 
in another. After the telescopic search which I was conduct- 
ing had been temporarily brought to an end, by circumstances 
beyond my control, I was not without hope of effecting some 
arrangement whereby I might resume the search at an early 
day, and carry it to a satisfying conclusion. After much 
thought upon the apathetic reception with which the magnifi- 
cent researches of Adams and LeVerrier had met, I reached the 
conclusion that no competent observer would be led to continue 
the search through knowledge of the little work of speculation 
that I had done. And, as the work was undertaken with the 
end always in view of finding the planet, I saw no good to 
Professor Forbes’ paper, will not appreciably destroy the repre- 
sentation of the residuals with which I have dealt. I have not 
et been able to convince myself that the remarkable harmony 
of the results of the two investigations is simply a chance agree- 
ment; and, with the hope that the accumulated evidence of the 
existence of a far exterior planet may not fail to incite some ob- 
server in possession of sufficiently powerful telescopic means to a 
vigorous prosecution of the search, I have prepared this pre- 
liminary paper in order that attention may be called to the 
matter in sufficient advance of the now approaching opposition- 
ime. may add here that, should a careful and protracted 
search of the region adjacent to the indicated longitude prove 
unavailing, no more certain test of the existence of a trans- 
neptunian planet admits of application within the next few 
years than that of telescopic search of a limited zone extending 
entirely around the heavens—a search which I have been hop- 
ing, for more than two years past, for an opportunity to under- 
take, but which I see no present prospect of realizing. 
Nautical Almanac Office, Washington, August 4, 1880. 
