33 i Intelligence and Miscellaneous Articles, 



the upper flames ; and since these must cross one another, the 

 result was a coloured picture of crossing waves, than which none 

 more beautiful can be imagined. It was exactly, in form, like that 

 which ensues when two stones are thrown upon the surface of still 

 water; but it is distinguished by the magnificence of its colours. 

 I publish this notice preliminarily, iii order that this simple and very 

 instructive experiment may be repeated ; I intend, however, to sub- 

 ject the phenomenon to scientific investigation, because the few expe- 

 riments I have at present made have led me to the conviction that, 

 besides dust-particles, the hygroscopic moisture adhering to glass, 

 though ever so little, is capable of producing it. I believe, further, 

 that the degree of moisture may be inferred from the intensity of 

 the streaks. Though, perhaps, of little value in relation to meteo- 

 rology, it will incontestably give to many a physicist a good test 

 for the degree of dryness of his glasses. 



The results of my further investigations I shall likewise commu- 

 nicate to the Annalen. — Poggendorff's Annalen, vol. cxlix. pp. 126- 

 128. 



NOTE ON THE FILLING OF VESSELS WITH A VERY NARROW TUBE, 

 ESPECIALLY THE CARTESIAN DIVER. BY K. L. BAUER, OF 

 KARLSRUHE. 



Erick (PhysicaliscJie Teclinih) and Weinhold ( Vorschule cler Expe- 

 rhnentalphysih) recommend, in order to introduce a sufficient quan- 

 tity of water into a Cartesian diver (best consisting of a hollow 

 glass ball with a narrow tube), to partially expel the air by heating, 

 and then to dip the open tube into water. For this procedure, 

 however, or the use of the air-pump for the same purpose, another 

 method, very simple, can be substituted as follows : — 



1. Fill the cylinder intended for the diver-experiments with 

 water ; insert the empty swimmer in the usual position, in which 

 the tube is directed downwards, and close the cylinder with a caout- 

 chouc cap and binding-thread. 



2. Exert a strong pressure on the elastic covering, and, continuing 

 the pressure, incline the cylinder to the horizon so that the caoutchouc 

 cap is perceptibly lower than the foot of the cylinder, and the diver, 

 with the tube directed obliquely upwards, begins to ascend. At this 

 moment, or when the swimmer has arrived at the top, remit the 

 pressure, and air-bubbles will escape from the ball, which is now 

 'partly filled ivith water. If the cylinder had been completely in- 

 verted, so that in its new vertical position the cap had been quite 

 under the bottom of the cylinder, the diver would have ascended 

 with great velocity, especially if the pressure had been interrupted 

 immediately after the inversion. 



3. If the cylinder be now restored to its original erect position 

 (when the swimmer also returns to his initial place), and the above 

 process be repeated, one very soon succeeds in filling into the diver 

 so much liquid that, even after complete inversion of the cylinder, 

 he will not ascend at all if strong pressure be continuously applied 



