86 GEELMUYDEN. ASTRONOMICAL OBSERVATIONS. [NORW. POL. EXP. 
H. Latitude, Local Time, and Longitude. 
The time of observation is given by the hours and minutes of chronometer Hohwii and 
astronomical date. The Greenwich astronomical date and time is obtained by subtraction of the 
corresponding hours and minutes of the preceding Table, and the local mean time by addition 
of the numbers in the next column of the present Table, containing the correction of Hw to 
local mean time. The sum of the numbers of this column and those of the preceding Table 
will then give the East Longitude in time. 
For the latitudes determined by meridian altitudes of the Sun at sea, the date of local 
Noon is enclosed in brackets. 
When latitude and local time were determined simultaneously by means of the great Altazi- 
muth, the latitude is generally given to seconds of are, the clock correction to seconds of time, 
and the longitude to minutes of are or sometimes half minutes. When two pairs of stars were 
observed, the degree of reliability may be inferred from the concordance of the numbers. For 
observations with the Sextant or the small Altazimuth, the latitude is generally given to the 
nearest minute or tenth of a minute. 
When only one of the two elements was determined at a time, as was always the case 
in summer, the assumed value of the other, as used for the computation, is enclosed in square 
brackets. In this case there is also added a column of differential coefficients, containing either 
= or = where dy is the increment of latitude corresponding to an increment dt of hour angle 
We 
(or clock correction or east longitude). In order to have the change of clock correction, corres- 
ponding to a given change of latitude, expressed at once in seconds of time, when the change 
of latitude is given in seconds of are, the differential coefficient in the last case is given in the 
form +. dé 
dy 
For the observations taken at sea, these differential coefficients do not always correspond 
exactly to the coordinates here given, as they have in many cases already been used for the 
correction of preliminary values. 
When observations of the Sun have been treated in the same manner as observations of 
two stars, the result will be found between the lines containing the times of observation. 
