539 
ON FIXING POSITIONS 
33T TEE 
MORE SIMPLE ASTRONOMICAL OBSERVATIONS, 
EOR THE USE OE 
R.A. OFFICERS ENGAGED IN EXPLORATION, 
BY 
MAJOR E. S. GORDON, R.A. 
The following brief summary of some of the handiest methods of 
determining Latitude, Longitude, and Compass Variation, is submitted 
for the use of R.A. officers on foreign stations who may be starting 
from thence on journies of exploration, in which they wish to obtain 
accurate and useful Geographical results—in the hope that the hints 
offered may be found useful to them in such expeditions, when 
frequently, from defective maps or other causes, independent observa¬ 
tions are found absolutely necessary. 
Treatises on this wide subject, which generally also deal much in 
theory, are mostly bulky and expensive; it is therefore hoped that to 
bring together a few of the most important practical operations may 
not be out of place in these <e Proceedings.” They are not intended to 
take the place of, but rather to induce to, a more extended study of 
the question. Beyond a general acquaintance with the methods of 
computation, nothing further is required than the ordinary knowledge 
of logarithms, and fair proficiency in the use of the sextant and mer¬ 
curial horizon. 
The author is indebted to his friend Mr. Coles, Instructor in 
Surveying and Mapping to the Royal Geographical Society, who has 
kindly looked through the paper, and supplied a valuable table (A) of 
Reductions for Hour Angles in Time, together with the hitherto un¬ 
published forms for working out examples here given, containing 
directions for application of the rules to different circumstances. Blank 
copies of these forms prepared beforehand will be found of great use in 
computing observations. 
It is proposed to discuss the following operations - 
I.—Finding the Latitude. 
(a) By Meridian Altitude of the Sun . 
(b) By Reduction to the Meridian. 
(c) By Altitude of Bole Star out of Meridian. 
Subjects. 
