On the Meteors of 13th November, 1833. 145 
Although these elements indicate a parallax in the right direction, 
yet there is some want of correspondence between the amount of par- _ 
allax and the differences of latitude in the several cases. Between 
New Haven and Worthington, the parallax in Dec. is only 1° 30’, the 
difference of Lat. being 1° 14’, while between New Haven and Em- 
mittsburg, the parallax is 3° 45’, the difference of Lat. being 1° 38.’ 
Owing to the want of correspondence between these elements, we 
_ shall form a different estimate of the distance, according as we derive 
our data from one pair or another of these observations. The appa- 
rent radiant being stationary, we may suppose the Dec. taken by each 
observer, at the moment when that point was on his meridian. ‘The 
difference of Lat. will represent the distance corresponding to the par- 
allax. Neglecting for the present all considerations of the earth’s 
spherical figure, and of refraction, we may in a very simple man- 
ner, obtain an approximate expression for the distance as follows. 
Let AB represent a horizontal line, and the angle BCD, the alti- 
tude of the radiant point, 74° 5’, as seen at Emmittsburg, in Lat. 
39° 40’, C being the place of observation. Let A be the place of 
observation at New Haven, in Lat. 41° 18’; then the angle at D will 
represent the parallax in Dec., namely, 3° 45’, and the angle 74° 5/— 
3° 45’=70° 20’=CAD; and the side AC=1° 38’=112.7 miles. 
Hence, Sin 3° 45/ Lye) SE LOA Ge Ree 
Sin 74° 5/ Dei ME KG ONG eatae 
112.7 LOE Sy i dna eh Na OY 
12.034946 
TGS OS is jimesheiclb SN bits hk Wg BUCROa a 
That is, the observations at Emmittsburg, compared with those at 
New Haven, give the distance from New Haven to the source of the 
Meteors, sixteen hundred and fifty seven miles. 
Fig. 1. Fig. 2. 
3° 45/ 
D 
745” 
A Cc 
Vou. XXVI.—No. 1. 19 
