M. Dvorak on Acoustic Repulsion. 225 



fixed stars in our sidereal system are all under each other's 

 influence through gravity. Two stars approaching each other 

 through gravity would at the same time be under the influence 

 of other neighbouring stars, drawing them from the right line 

 towards each other's centre. Therefore they would not col- 

 lide ; but they might approach very near to each other, so as 

 to remain permanently within their powerfully gravitating 

 force, and form a binary system. This is a mode of accounting 

 for the ten thousand double and multiple stars already known, 

 besides the mode of explanation by the nebular theory. More- 

 over the nebular theory necessarily gives very high velocities 

 to all the stars, but to all in the same direction. If afterwards, 

 by perturbation, they receive contrary directions, still the mo- 

 tions of any two precisely toward one another would be the 

 most improbable of events. 



Therefore the mechanical theory of stellar light and heat 

 utterly fails in all its phases. The only true theory for the 

 " ignes seterni " is that of chemical action. This also has been 

 abruptly denied, but only by those entirely unacquainted with 

 the foundations of that theory as explained by myself in ' The 

 Origin of the Stars ' and in subsequent papers. 



XXIX. On Acoustic Repulsion. By V. DvorAk*. With a 

 Note by Prof. A. M. Mayer. 



1. ACOUSTIC Repulsion of Resonators which are open at 

 "^ one end only. — In a previous article, " On Acoustic 

 Attraction and Repulsion," I have conclusively proved by 

 theoretic considerations, as well as by experiments, that the 

 average pressure at the node in a column of air vibrating in 

 stationary waves cannot be equal to zero as long as the ampli- 

 tude of vibration is not infinitely small. 



In a resonator open at one end, as, for example, a cylinder, 

 we find a node at the closed end. In the interior of the cy- 

 linder near its closed end there exists a greater pressure than 

 on the outer surface of this end which is touched by the out- 

 side air, as can easily be shown by means of a sensitive mano- 

 meter. 



To obtain resonance the opening of the cylinder is turned 

 toward the source of the sound ; and the cylinder is then re- 

 pelled by the excess of pressure within. Resonators not having 

 a cylindrical form, but open at one end, are also subject to such 

 repulsion. In my previous communication I have indicated 



* From the American Journal of Science and Arts for July 1878. 

 Translated from the Annalen der Physik und Chemie, Band iii. No. 3 ; 

 dated Agram, November 19, 1877. 



Phil, Mag. S. 5. Vol. 6. No. 36. Sept. 1878. Q 



