226 



APPENDIX. 

 *' The Latitudes of the (liip were determined moft com- 

 " monly by the meridian altitude of the Sun's lower limb; 

 «< in a few inftances, by that of his upper limb, when the 

 " lower was not fo diftinft, or was hid by clouds. The 

 " heio-ht of the eye above the level of the fea, in all thefe 

 »' obfervations, was fixteen feet. When we could not get 

 *' a meridian obfervation, we made ufe of the method 

 " defcribed in the Nautical Almanac for 177 1, from two 

 " altitudes taken about noon, and at a little diflance from it. 



" It fometimes happens that we can only take fome 

 " altitudes very near the time of noon- If we have 

 «' obferved any altitudes of the Sun near the prime vertical, 

 " we may thence determine how much the watch is too 

 *' fafl: or too flow for apparent time ; and confequently, 

 " how much the time when the altitudes were taken, is 

 *' diftant from noon; it therefore remains to find how 

 " much thefe altitudes are different from the meridian 

 " altitude. This may eafily be found by the following 

 <' Rule : 



*' To the logarithm of the rifmg, taken out of the 

 " tables in the Nautical Almanac for 1771, add the com- 

 *' plement arithmetical of the logarithmic cofine of the 

 *' fuppofed meridian altitude ; from the fum (the index 

 " beincr increafed by five) fubtract the logarithm ratio 

 *< (found by the rules in the abovementioned Ephemeris) 

 " the remainder is the logarithmic fine of the change in 



*' altitude. 



«EXAMFLE» 



