440 MR. THOMAS HEELIS'S OBSERVATIONS 



The variations in the latitude of the apex shown in the 

 above Table are remarkable. Some are no doubt due to 

 errors of observation, although every care was taken to 

 guard against such. If we refer to the observations of 

 Cassini, given by Mr. Jones at the end of those made by 

 him during the United States Expedition to Japan, we 

 shall find that, although the body of the light is seldom 

 equally distributed on each side of the ecliptic, the apex 

 has only on two occasions decided latitude, and that on 

 those two occasions the latitudes are N. The observations 

 are 21st April 1685, in which the apex has a latitude of 

 5° N., and the 15th October 1687, in which the latitude is 

 about 4° N. These observations seem to have been made 

 at Paris, and Cassini mentions that the apex had N. lati- 

 tude towards the end of April 1683, and that that circum- 

 stance had caused him to think that its plane nearly coin- 

 cided with the sun^s equator. Mr. Jones compares the 

 first of these observations with a set made by him on the 

 2 1st April 1854 in lat. 34° 40' N., long. 138° 59' E., from 

 the chart of which it appears that at 7^ 52"^ the apex was 

 nearly in the position which it occupies in Cassini^s ob- 

 servations, but that it had greater N. latitude (about 6°), 

 and that by 9 p.m. this apex was visible some 15° further, 

 but that its N. latitude had decreased so as to be little 

 more than -2°. He also compares Cassini^s observation of 

 the 15th October 1687 with two of his own, made on the 

 1 6th and 20th October 1854; but on reference to the 

 plates it will be found that Mr. Joneses observation of the 

 1 6th is incomplete, the apex being merged in the Milky 

 Way. Enough, however, is shown to assure us that the 

 great mass of the light is on the south side of the ecliptic, 

 whereas in the observation of Cassini it is on the north. 

 The American observation was made in 33° 16' N. long., 

 1 77° 28' W. The American observation of the 20th October 

 1854 is also defective, on account of the apex being merged 



