bees 
By Mercator’s failing, 
Set the femicircle to the proper latitude failed from, and the 
index to the courfe; mark the diftance on it, and bring the 
perpendicular to the diftance failed; which at the fame time 
will mark the latitude arrived at on the line of proper lati- 
tude 61° 20'S.; fcrew the index to the courfe, and move the 
femicircle and perpendicular to the meridional parts of both 
latitudes, then the index will cut the difference of longitude 
on the perpendicular 5° 35’. 
By middle Latitude failing. 
Finp the latitude arrived at as above, and then find the 
difference of longitude as found by middle latitude failing in 
the preceding cafe. 
CiANS Bre Mil: 
One latitude, courfe and departure given, to find the diftance, 
difference of latitude, and difference of longitude. 
Lat. 56° 40’ N. Long. 28° 55’ W. 
Courfe N. 31° 35° W.; departure 172.7 miles. 
By Mercator’s failing. 
Move the femicircle to the proper latitude failed from, and 
the index to the courfe. Mark the departure on the perpen- 
ag dicular, 
