Some Books Recently Received

The aeronautical engineer is all the time struggling to improve aircraft performance. His problem is essentially the attainment of maximum economy—to get the maximum duty out of the material at his disposal. In the field of aerodynamics his progress depends upon the progress of his knowledge of the behaviour of air in a variety of circumstances. In the field of structures it depends upon the exactness of his knowledge of the distribution of stress and strain. In the field of oscillations, where the influences of aerodynamics, structures and inertia combine, he needs the support of the theory of vibration.