M. . Transactions. 
The position of Rapa is in 273? S. latitude, and 144? W. longitude ; 
about 700 miles S.E. of the Society group, and some 4° S. of the tropic-of 
Capricorn, and as nearly as possible two-thirds of the distance between 
Panama and. Wellington. 
Very little was generally known about the island till lately, and nothing 
of its being favoured with so perfect a harbour. The finding it out was 
the result of very many inquiries I made from every one I could hear of 
who had been to the South Sea Islands, as to the existence of some suitable 
spot where we might have a coal depót; for, on the establishment of the 
Panama service, I was so impressed with the desirability, if not necessity, 
of some stopping-place near the route, that I used every effort for months 
endeavouring to find one. At last I was rewarded for my pains by hearing 
of Rapa. Its situation, juston the outer verge of the Southern Archipelago 
and in the direct track (not the direct line) between Panama and New Zea- 
land, makes it partieularly advantageous as a place of call in case of acci- 
dent or deficiency of fuel. 
And, speaking of the track of the stedmers between N ew Zealand and 
Panama, I will for an instant advert to the difference of route in going 
towards Panama and returning from it. 
Leaving Wellington we adopt what is called the “ great circle” course, 
which, though apparently roundabout, is in reality the direct and shortest 
line to Panama. Now, in returning from Panama to Wellington we appear 
to adopt a much straighter course, but it is really somewhat longer. This 
is readily explained by reminding you that we are not sailing upon a level 
but a curved surface. Take a round body to represent the earth, a thread 
stretched between any two points is evidently the shortest distance between 
them, and, viewed in a line with the centre, is straight. This should be the 
ship’s course. But on the chart generally used this straight line will appear 
a curve, and all the straight lines (meridians excepted) are really curves. 
And although Mercator's projection, as it is called, is the most simple for 
the ordinary purposes of navigation, yet it has led many people, and even 
seamen, to have confused ideas upon this very simple subject. In the track 
upwards to Panama the winds are frequently found favourable, because the 
course lies principally in the well-known belt of westerly winds. From 
Panama we keep further north, through the heart of the easterly or trade 
winds prevailing generally, though varying with the seasons, between the 
equator and the southern tropic. In this part of the voyage the winds are 
less favourable than the other, and particularly in the latter part. Trying to 
avoid the westerly or adverse winds which prevail further south, we adopt 
: » Which brings us close to Rapa, from which, I fear, you will think 
‘made too long a "sion —— : i 
