94< Mr. Lax’s Method of finding the Latitude of a Place , 
a^b^c^d:a^br^m^?i::a^ c : the quantity to be 
added to, or subtracted from, a, to make it of the required mag- 
nitude. We have then only to subtract m from this corrected 
value of a , to proceed with the remainder to the second table, 
and take out the corresponding error in the assumed latitude. 
This precaution, however, can very seldom be necessary; and, 
even when it is deemed advisable to adopt it, the division may be 
performed with so little regard to exactness as to render the 
process easy and expeditious. 
But we are not to conclude that, because this inaccuracy, and 
also the two first species that were considered, are likely to be 
introduced, when the latitude and declination are nearly equal 
and of the same kind, they will therefore unavoidably exist in 
these circumstances.- On the contrary, they may always be pre- 
vented, when the weather is favourable, by making the observa- 
tions within a smaller distance from the meridian. We have 
only to wait till the increase of the sun’s altitude becomes so 
slow as not to produce a visible separation of the limbs in two 
or three seconds, and then we may be assured that the azimuth 
is small, and consequently that none of these errors will be consi- 
derable. 
I have hitherto supposed that this method is only to be 
adopted, when the sun, at each observation, is within fifteen de- 
grees of the meridian; or (to speak more accurately) when 
both the azimuth and the hour-angle are so small that we may 
consider their tangents as bearing a given ratio to each other ; 
and, indisputably, these limits should never be transgressed, 
when it can possibly be avoided; for we have seen (page 79 th) 
that, whatever be the method employed, the smaller the 
