be deôÙterôÙmined by the inôÙterôÙsecôÙtion of two such circles; and the angle DBO is then the angle, öÝ, required.
Or we may determine, graphically, at two points, the radii of curvature, üÿ£¢1üÿ£¢2ã₤. Then, if s be the length of the arc between them (which may be determined with fair accuracy by rolling the margin of the shell along a ruler)
The following method22, given by Blake, will save actual determination of the radii of curvature.
Measure along a tangent to the curve, the distance, AC, at which a certain small offset, CD, is made by the curve; and from another point B, measure the distance at which the curve makes an equal offset. Then, calling the offset ö¥; the arc AB, s; and AC, BE, respectively xÿ£¢1ã₤, xÿ£¢2ã₤, we have
Of all these methods by which the mathôÙeôÙmatôÙiôÙcal constants, or specific