Committee on science and the arts

In contradiction to results previously reported, it has been found that DNA prepared by a method which utilizes strong NaOH is acted on by the specific nuclease, although at a rate only 20 per cent. of that of DNA prepared by a milder method. The nature of the changes responsible for the low rate of hydrolysis of the alkali-treated DNA are not known.     

Stability of oscillations in systems obeying Mathieu's equation

Numerous relatively simple physical systems give rise under appropriate circumstances to oscillations which obey the equation y″ + ?(1 + k cos t)y = 0 (Mathieu's equation). These oscillations may be either stable, periodic, or unstable, depending upon parameters of the physical system as expressed by the parameters ? and k in the basic equation. It has been customary to distinguish between the stable and unstable states by diagrams of the type of Fig. 1, from which it is possible to tell whether a given set of values of the parameters ?, k will yield a stable or unstable solution. In this paper are given curves which not only present this information, but in addition give for an important part of the stable state the values of the characteristic exponent μ. The solution of the equation y″ + ?(1 + k cos t)y = 0 depends to a large extent on this exponent, and the availability of values of μ should greatly facilitate the practical application of the equation.