This pumping action results in an extremely rapid circulation of the heating agent, enabling long distances to be traversed without much loss of heat.
Any line cuts off equal distances between the curve and the asymptotes.
The problem, however, of constructing a deep-sea cable satisfactorily, with suitable inductance coils inserted at short distances apart, is a difficult one, and one which it cannot be said has been solved.
An important property is: the difference of the focal distances of any point on the curve equals the transverse axis.
The fundamental difference between the two methods is that while the mechanical energy developed by a steam engine is in the first case applied directly to the driving-axle of the locomotive, in the second case it is transformed into electrical energy, transmitted over relatively long distances, and retransformed into mechanical energy on the driving-axles of the train.