What I think of on this point is, when self is the fixed point the centripetal force is balanced with the centrifugal.

The most simple and familiar portion of time, applicable to the subject was that of a year; and hence the doctrine has been inculcated by a laudable zeal, to erect some barrier against the gradual innovations of an unlimited government, that the advance towards tyranny was to be calculated by the distance of departure from the fixed point of annual elections.

We must suppose the Melipona to make her cells truly spherical, and of equal sizes; and this would not be very surprising, seeing that she already does so to a certain extent, and seeing what perfectly cylindrical burrows in wood many insects can make, apparently by turning round on a fixed point.