That to fit the actions and distances covered by Alexander into such a scheme, assuming that he went by Seistan and Kandahar, would involve physical impossibilities has been pointed out by Count Yorck v.
An important property is: the difference of the focal distances of any point on the curve equals the transverse axis.
The tangent at any point bisects the angle between the focal distances of the point, and the normal is equally inclined to the focal distances.
This pumping action results in an extremely rapid circulation of the heating agent, enabling long distances to be traversed without much loss of heat.
Owing to the great distances which must be covered, and also to the defective means of communication in sparsely settled districts, the costs of the postal service in Argentina are unavoidably high in relation to the receipts.