An essay on comets, in two parts : part I, containing an attempt to explain the phenomena of the tails of comets, and to account for their perpetual opposition to the sun, upon philosophical principles : part II, pointing out some important ends for which these tails were probably designed ... : the whole interspersed with observations and reflections on the sun and primary planets / - Oliver, A. (Printed and sold by Samuel Hall,, 1772)