( 4 
HINTS TO TRAVELLERS. 
VOL. I. 
/ 
SURVEYING AND ASTRONOMICAL OBSERVATIONS. 
By John Coles, f.b.a.s., late Instructor in Surveying and. Practical 
Astronomy to the Royal Geographical Society; and others , 
PART I. 
INSTRUMENTS USED FOR ASTRONOMICAL 
OBSERVATIONS AND SURVEYING. 
Preliminary Remarks.— The intending traveller who proposes to under¬ 
take the survey of an unexplored country, should make himself acquainted 
with the use and adjustments of every instrument he purposes to employ ; 
he should have a knowledge of plane trigonometry, and those computa¬ 
tions of practical astronomy which are necessary to enable him to fix his 
position in latitude and longitude; and although from his note-book he 
may furnish cartographers with valuable material, yet, without such 
previous training, it is scarcely possible for him to map the country 
through which he travels, nor will he be able to take full advantage of these 
4 Hints,’ as the greater part of the matters dealt with will be beyond his 
comprehension. The attainment of this necessary amount of knowledge 
is by no means difficult, and a few weeks of study, under proper instruct 
tion, ought, in most cases, to enable him, by the aid of the following 
pages, to do useful geographical work. It is with this end in view that 
this volume of * Hints tQ Travellers ’ has been written in the simplest 
form. 
Yol. i. 
B 
