So Mr. Lax’s Method of finding the Latitude of a Place , 
I might perhaps be allowed to say more ; for I am satisfied, 
from experience, that I can take an altitude of the sun with 
greater exactness, when he is in any other situation, than when 
he is upon the meridian. If we could ascertain, within a few 
seconds, or even within a minute, the time when he attains his 
greatest altitude, there would then be no reason why an ob- 
servation should not be made with the same degree of cer- 
tainty in this, as in other cases ; but we are generally obliged 
to keep our eye stedfastly fixed, for several minutes, upon the 
two images, and it is well known that, in such circum- 
stances, the best eyes are apt to be deceived. Besides, it is im- 
possible to preserve the contact of the limbs by perpetually 
moving the index, whilst the sun continues to ascend so very 
slowly. We are compelled to wait till they are evidently sepa- 
rated, and then, by one turn of the screw, to bring them into 
contact again, which must necessarily be a source of some inac- 
curacy. It is for the first of these reasons that, in taking an 
altitude of the sun, when he is near the meridian, I have found 
it advisable, not, in the usual manner, to bring the images 
almost to touch each other, and then to wait till they actually 
do so, but to bring them at once into contact, with such a de- 
gree of velocity as would make them sensibly overlap, or sepa- 
rate, whilst the clock beats a second. 
But I consider it as one of the principal advantages of this 
method, that we can avail ourselves of any number of altitudes, 
and, of course, approximate as near as we please to a true 
conclusion with so little additional labour. If there be an 
equal number of observations made on each side of the meri- 
dian, we must combine them together by pairs, according to 
the preceding instructions, and thus determine the different 
