134 JOHN TEBBUTT. 



Sydney time, the comet was approaching the plane of the terrestrial 

 orbit from the northern region of space. On that date it crossed 

 the plane at a distance of 966 millions of miles from the sun, and 

 thereafter its course lay south of the ecliptic. On April 1st last, 

 the comet was detected by Mr. Gale just before it attained its 

 extreme limit of south declination. On the evening of April 3rd 

 when my first observations were made, the earth and comet were 

 almost exactly equidistant from the sun, namely 92,400,000 miles. 

 The comet's distance from the earth, however, was eighty millions. 

 It will be seen by a glance at the table of observed places appended 

 to this paper that the comet reached its greatest south declination 

 on April 5th and thereafter proceeded northward with daily 

 increasing rapidity. It arrived in perihelion at twenty-two 

 minutes past ten o'clock a.m., Sydney mean time, on April 14th, 

 at a distance of ninety-one millions of miles from the sun. It 

 then receded slowly from the sun, but at the same time rapidly 

 approached the earth, arriving at its closest approximation to our 

 planet, about thirty-one millions of miles, in the beginning of 

 May. On May 11th at forty-two minutes past three o'clock 

 a.m., the comet, in accordance with prediction, again crossed, 

 the plane of the earth's orbit, but this time northward and at 

 a point only seven and a-half millions of miles outside of th& 

 earth's path. The earth, however, had passed the place of near 

 approach of the two orbits on April 16th, so that at the time 

 of the comet's nodal passage, the earth was really twenty-four 

 days in advance in her annual path, and consequently about forty 

 millions of miles distant from the comet. If the comet had arrived 

 in perihelion about March 21st instead of April 14th, it would 

 have been close to the earth and thus have presented a more 

 imposing appearance. At the time of my last observation, May 

 11th, the comet had attained to a distance of one hundred and one 

 millions of miles from the sun and forty-one millions from the 

 earth, and at the present time while I am reading this paper these 

 distances have increased to one hundred and fifty-four and one 

 hundred and sixty-three millions respectively. Its light has. 



