; 



^ S R, 159 



III. ANALYSIS AND SYNT 



scheihe), for demonstrating the wave undulation. The eight drawings are 

 for the purpose of illustrating the water, rope, sound, and air waves, in covered 

 as well as in open pipes. 



See " Lehrbuch der Physik," VII. Edit. Vol. I., 155). 



726. Telephon, on Reis' system, for the reproduction of 

 sounds by galvanism. 



J. Wilhelm Albert, Frankf or t-on-the- Maine. 



2. The telephon is based on the experiments of Wertheim and others 

 regarding galvanic sounds. Philipp Iteis, at Friedrichsdorf, made use of these 

 with a view of reproducing by means of galvanic action the musical sounds 

 produced by singing (or by pipes, &c. played upon), by employing an elastic 

 membrane and an interference apparatus constructed by him. 



(See Jahresbericht des physikalischen Vereins zu Frankfurt a Main. 

 Jahrgaug 1860-G1 ; also, "Miiller's Lehrbuch der Physik, VII. edit. Vol. II., 

 135. 



727. Crank Apparatus, for showing the production of pro- 

 gressive (water, &c.) waves. 



Prof. J. Joseph Oppel, Frankf or t-on- the- Maine. 



The rotating liquid molecules are represented by white wooden balls on 

 a black background, and are all put into motion by a crank attached at the 

 back. 



The whole shows two wave lengths. 



728. Cylinder Apparatus, for showing directly and com- 

 paratively progressive and stationary waves of sound, and respec- 

 tively the essential difference between both. 



Professor J. Joseph Oppcl, Frankf or t-on-the- Maine. 



Contains 1^ corresponding wave lengths on both cylinders. Other 



drawings likewise, for example, with different wave lengths (for illustrating 



the musical intervals, &c.), can be mounted on the cylinders, which are of a 



somewhat conical shape. 



729. Two Wave Discs of paste-board for stroboscopic 

 illustration of a progressive and a stationary (water) wave. 



Professor J. Joseph Oppel, Frankf or t-on-thc- Maine. 



Would be best fastened to a rotation apparatus such as are used for 

 colour spindles, &c., and placed in front of a mirror. All waves, with the 

 exception of a horizontal one, should be covered by a black screen. 



730. Brass Tube, with Gas-burner, for Intonation. 



(Compare Poggendorff's Anualen, vol. 129, 1866.) 



A Ibrecht, Tiibinge n . 



731. Rotating Mirror, movable towards all sides. 



Albrechtj Tubingen. 



been 



This mirror has not yet been described, but several specimens have already 

 en executed by Mr. Albrecht. That position of the mirror in which its 



