359 
No. 4, 3s. W. of Greenwich; error 33s. 
A second set of observations gave at 8h. 5m. 13s. local 
time, true alt. of Moon 65° 29‘ 20"; true alt. of Sun 24° 10° 0"; 
true app. dist. of their centres (mean of three observations) 
63° 20° 27". 
These data, when computed on the Ist method mentioned 
above, give the long. of the place Im. 35s. E.; error Im. 5s: on 
the 4th method Im. 29s. E.; error 59s. It was thought 
unnecessary to make the calculations again on the 2nd method, 
because its form is nearly the same as that of the first; on the 
3rd, because its result in the previous case differed considerably 
from the other three. 
The bar. and ther. were not taken into account, as neither 
of them were far from the point at which they do not affect the 
refraction. The index error of the instrument was too small 
to be ascertained by any one but a very good observer. The 
inaccuracy of the second set of observations might be due to a 
haze coming on at the time, and to the increasing brightness of 
the Sun. 
Several extracts were also given from the voyages of Cook 
and Krusenstern, bearing on the accuracy with which it was 
found practicable to use this method of fixing the long. at the 
end of the last and the beginning of the present century. For 
example, the long. of Santa Cruz (Teneriffe), where Cook is 
described (Voyage, Vol. 1.) as bovine met Borda in August, 1776, 
was given by the latter as 18° 35' 30° W. of Paris, Cook making 
it by his timepiece 16° 31' 0", by two sets of lunars 16° 30°45" W. 
of Greenwich. The true long. as given by the English Ad- 
miralty Chart (1873) being 16° 14° 56" W. of Greenwich, or 
18° 35° 6° W. of Paris. ; 
