weight. Then, from the would continually coincide with the meridian, notwithstand- known density of lead and the law of gravitation that bodies ing the rotation of the earth, and would appear unchanged. attract each other directly as their masses and inversely as In latitudes between the equator… … Fig. 1, a drawing by Professor MacCord, neatly illustrates by the reflection of a beam of sunlight by means of a mirror, From the dimensions of the earth already given, its vol- he reason why the amount cf deviation in the plane of oscil- called a heliotrope, into the measurement. The observations…
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