of the meteor of 1807. 219 
The sum of the angles Cwm, mCw, subtracted from 180° leaves Cmw. 
Then 
Sine Cmw : Sine Cwm :: Cw: Cm 
The distances wm, sm, and the latitude and longitude of the mete- 
or may be found as in Problem 1. 
When the distance of the meteor is great, the angles Csm, Cwm, 
must be corrected for terrestrial refraction, by subtracting one four- 
teenth part of the intercepted arches SM, WM respectively ; but as 
these arches are generally unknown, it will be necessary (when great 
accuracy is required) to make the calculation with the altitudes un- 
corrected, and thus find the approximate values of the corrections of 
the altitudes for refraction, and, by repeating the operation, the required 
quantities will be obtained. In this way the refraction in the Wenham 
observations was found to be about 9 or 10 minutes. 
EXAMPLEs 
Suppose the altitude of the meteor at the time of its disappearance 
at Weston was 75°, its azimuth at that place N 15° W, and the cor- 
responding altitude of the meteor at Wenham 5° 30’ corrected for re- 
fraction. It is required to find the latitude and longitude of the me- 
teor, its distance from Wenham and Weston, and its vertical altitude 
above the level of the sea. 
Here are given the angle Cwm = 90° +alt. at Wenham = 95° 30’, 
Csm=90° + alt. at Weston=165°. The arch SW= 2°24'25", 
_ the angle PWS = 125° 18’ 38”, and the angle PSW = 52° 56’ 34”, are 
found as in the last example. The angles PSW, PSM added togeth- 
er give WSM or ASW = 67° 56’ 34”. 
This corresponds to Example 14, Table 1. 
