[) heeo: a) 
dicular, and move it until the termination thereof meets the 
index, then the point of interfeCtion will fhow the diftance 329 
on the index, and the perpendicular will fhow the latitude arrived 
at 61° 20’ N. on the bafe. 
THEN fcrew faft the index, and move the perpendicular and 
femicircle to the meridional parts correfponding with both lati- 
tudes, then the index will cut the difference of longitude, 
5° 35’ on the perpendicular. 
By middle Latitude failing. 
Finp the latitude arrived at and the diftance as above, and 
the difference of longitude as in cafe IV. by middle latitude 
failing. 
CASE VIE 
One latitude, diftance failed and the departure given, to find 
the courfe, difference of latitude, and difference of longitude. 
Lat. 48° 30 N. Long. 14° 40’ W. failed from. 
Diftance fouth eafterly 345 miles, and departure 200 miles. 
Movs the femicircle to the latitude departed from, mark the 
diftance on the index and the departure on the perpendicular, 
move both until thefe points meet, then will the index fhew 
the courfe 8S. 35° 26’ E. on the femicircle, and the perpendicular 
the latitude arrived at 43° 49° on the bafe.. 
THE 
