PAPER BY PROF. OBERBECK. 



149 



Fig. 25. 



materially larger than that of the jet, then the latter will be deviated 

 at the plate through a right angle and flows in a thiu layer radially 

 along the plate, which it leaves in a horizontal direction, as in Fig. 25. 



If, on the other hand, the 



(cP ~^ / == ^ radius of the paitition is 



only a little larger than 

 the radius of the jet, then 

 will the stream lines be de- 

 viated by a smaller an- 

 gle from their original 

 direction. This process is 

 shown in Fig. 26, which 

 has a great similarity to 

 the drawing given by Kirchhort at the place just 

 refered to.* 



A thin sharp-edged partition that extends to 

 about the center of the jet exerts a very similar Fi g .36. 



influence to the thin circular plate. In this 



case, while one part of the jet spreads in a thin layer along the plate 

 the other part is deviated through an acute angle. In this experiment 

 also the material of the plate appears to exert no sensible influence on 

 the course of the stream. Disks of thin glass and of glazed drawing 

 paper were used, while the above-mentioned thiu partition was replaced 

 by a sheet of tinfoil, which was stretched over a glass frame, and one- 

 half of which had been removed along a straight line. The stream 

 phenomena remained exactly the same. The angle by which the J2t in 

 this last case was deviated from its initial direction depended princi- 

 pally upon the depth to which the thin partition penetrated into the jet. 

 The phenomena here described of flow against solid bodies succeeded 

 only for small velocities of the jet such as corresponded to differences 

 of pressure of 20 or 30 millimetres. 



VII. 



Since it was the main object of the author to investigate discon- 

 tinuous liquid motions in their simplest form, therefore he has for the 

 present confined hims,elf at first to the above-described experiments. 

 Still these shall be extended as soon as possible in different directions. 

 As the next points for study the following especially commend them- 

 selves: 



(a) The flow of a colored liquid into a colorless one through an open- 

 ing in a thin partition. Some preliminary experiments with an imper- 

 fect apparatus showed that the jets thus formed are similar to the above 

 described under otherwise similar circumstances. 



(b) The discharge of a liquid into another liquid of equal specific 

 gravity that is not iniscible with the first liquid. In this experiment 



* [See No. VIII of this collection of Translations.] 



