Plane trigonometry with practical applications, by Leonard E. Dickson.

172
Meridional parts, 72.
difference of lat., 74.
Middle latitude sailing, 68.
Mil, 160.
Mollweide's equations, 117.
Natural functions, 19.
Nautical astronomy, 59.
mile, 60.
Navigation, 59.
Oblique triangle, 115.
Octagon, 54.
Ordinate, 103.
Origin, 104.
Parallel of latitude, 60.
sailing, 66.
Parallelogram of forces, 29.
Parts of triangle, 21.
Patent log, 61.
Pentagon, 53.
Perimeter, 129.
Piloting, 59.
Plane Sailing, 62.
Plotting, 88, 104.
Plumb line, 4.
Points of compass, 61.
Poles, 59, 94.
Polygon, 53.
Protractor, 1.
Quadrants, 106.
Radian, 158.
Radius vector, 104.
of inscribed circle, 129.
Rational, 35.
Reciprocal, 7.
Refraction of light, 31.
Relative error, 3.
Resultant of forces, 29, 131.
Rhumb line, 68, 73.
Right triangle, 19, 48, 125.
Sailing, Mercator's, 73.
middle latitude, 68.
parallel, 66.
plane, 62.
traverse, 64.
Secant, 7, 107.
curve, 155.
Sight vane, 91.
Significant, 38.

INDEX
Sine, 6, 7, 107.
arc, 165.
curve, 152-3.
inverse, 165.
law of, 115.
of small angle, 161.
Slide rule, 44.
Slope, 5.
Spirit level, 4.
Square-ruled paper, 2, 104.
Stadia wires, 99.
Statute mile, 60.
Subtraction theorems for sine and cosine, 136.
for tangent and cotangent, 138.
Surveying, 82.
instruments, 89.
Tangent, 5, 7, 107.
curve, 154.
law of, 117.
of 90~, 155.
of small angle, 161.
Tape, 82.
Telescope, 96.
Trajectory, 142.
Transit, 96.
Traverse, 99.
sailing, 64.
table, 26, 63.
Trigonometric equations, 147, 156, 162.
Trigonometric functions, 6, 107.
inverse of, 164.
line representation, 150.
of double angle, 140.
of half angle, 144.
of multiple angle, 141.
of several angles, 133.
reduced to acute angles, 111.
sum of, expressed as a product,
145.
True bearing, 83.
course, 61, 77.
Undefined, 108, 154.
Unit's place, 38.
Variation, 76, 94.
charts, 95.
Vernier, 89, 95.
double, 90.
plate, 96.
Vertical angle, 4.
circle, 98.
line, 4.
plane, 4.