OBSEEVATIONS AND ORBIT-ELEMENTS OF COMET GALE. 135 



diminished in apparent intensity to one-tenth of that for April 3rd 

 last, and a telescope of considerable power is therefore now 

 required to observe it. 



Appended to this paper will be found the complete results of 

 my observations. The reductions have been troublesome in con- 

 sequence of the rapid motion of the comet, both in right ascension 

 and in declination. Having no means for observing with a filai. 

 micrometer in a dark field I was obliged to employ a square bar- 

 micrometer. I do not, however, complain of the additional reduc- 

 tions for proper motion seeing that the work done with the same 

 micrometer has turned out remarkably well in various European 

 investigations of cometary orbits. The arrangement of the table 

 will not require any explanation beyond the circumstance that I 

 have substituted the logarithmic parallax factors -|> 1 for the usual 

 parallax logarithms p A, for the reduction of the observed positions 

 to the earth's centre. As the calculation of the factors referred 

 to does not involve any assumed parallax of the sun, the computer 

 can choose any value he pleases for this element. P represents 

 the equatorial horizontal parallax of the comet in seconds of arc, 

 and^9 and q the reductions in seconds of time and arc respectively. 

 In those cases where the comparison stars are found in Stone's 

 Cape Catalogue and the Glasgow Catalogues the precessions and 

 secular variations of those catalogues have been employed in the 

 reduction of the mean places to 1894*0. In all other cases the 

 precessions for the middle epoch between the year of the catalogue 

 and the current year have been calculated from Peters' elements. 

 The first comparison star is a wide double whose components 

 are both to be found in the Cordoba Zones and Stone's Cape 

 Catalogue, but in the latter authority the north polar distances 

 are transposed. 



