C 5 66 ] 
Minute 'of Latitude t on the rhumb Lire making 
Angles with the Meridians of $ 1 ° 38' 9". 
For, let rcprclent the meridional Difference of 
Latitude between two Places on the Rhumb of 45 
Degrees; or its Equal, the Difference between the 
logarithmic Tangents of. the Half-Complements of 
the Latitudes of thofe Places, eftimated either in 
Parts of the Radius , or in Minutes of a Degree. 
Then, 
As the Circumference in Parrs of the Radius 
= 62831,853 &c. 
To the Circumference in Minutes of a Degree 
> — 21600. 
So is a meridional Difference of Latitude in Parts of 
the Radius = z. 
To a meridional Difference of Latitude in Minutes 
of a Degree, = 0,34377468 &c. x 
Whole correfponding Rhumb is different from 
that which .c, belonged to; and the Angle which 
this Rhumb makes wirh the Meridian, will be found 
by the following Analogy from Art. 7. 
As the meridional Difference of Latitude on one 
Rhumb = o 34377468 &c. z. 
To the meridional Difference of Latitudc^on a Rhumb 
of 45 Degrees, = z. 
So is the natural Tangent of the Rhumb of 45 
Degrees, — 1 0000. 
To the natural Tangent of the other Rhumb, 
== 29088,82 1, &c. 
Which Tangent anfwers to 71° 1' 42"; and this 
is the Angle that the rhumb. Line makes with the 
Meridians, cn which the Differences of the logarithmic 
Tangents 
