604 
4. On the Banger of Hasty Generalisation in Geology. By 
Alexander Bryson, Esq. 
5. On the Deflection of the Plummet caused by the Sun’s and 
Moon’s Attraction. By Edward Sang. 
In this paper it was shown that the attraction of the sun causes 
a deflection of the plummet, having its maximum about the 240th 
part of a second, and proportional to the size of twice the sun’s 
zenith distance ; the deflection is at its maximum when the sun is 
45° above or below the horizon, and occurs in the vertical plane 
passing through the attracting body. 
The deflection due to the moon has its maximum about the 60th 
part of a second, and follows the same law ; it is toward or from the 
attracting body according as the zenith distance is less or more 
than 90°. 
Upon the cross-level of a transit instrument, the joint effect is to 
cause a semi-diurnal oscillation small at the quarters and rising to 
the 24th part of a second at new and full moon ; while the influence 
upon meridian observations is sufficient to cause a disagreement be- 
tween the greatest inclination of the moon’s orbit, as observed at 
St Petersburg and Madras, amounting to the 50th of a second. 
The general conclusion drawn was, that we cannot determine the 
positions of the heavenly bodies true to the 100th part of a second 
without having made allowance for this source of disturbance. 
6. Note on Gravity and Cohesion. By Professor William 
Thomson. 
The view, founded on Boscovich’s theory, commonly taken of cohe- 
sion, whether of solids or of liquids, is, that it results from a force 
of attraction between the particles of matter, which increases much 
more rapidly than according to the inverse square of the distance, 
when the distance is diminished below some very small limit. This 
view might, indeed, seem inevitable, unless the idea of “attraction” 
is to be discarded altogether; because the law of attraction at sen- 
sible distances — the Newtonian law — demonstrated by its discoverer 
for distances not incomparably smaller than the earth’s dimensions, 
and verified by Maskelyne and Cavendish in a manner rendering 
it impossible for any naturalist to reasonably doubt its applicability 
