164 SEC. 6. SOUND. 



748. A Model of Robert Wornum's method of returning 

 the hammer, in his down-striking Action for Horizontal Grand 

 and Square Pianofortes, patented in 1842. 



Messrs. Wornum $ Sons. 



This action greatly economises the cost of manufacture. The usual actions 

 are up-striking. 



749. A Model of Alfred Nicholson Wornum's new Patent 

 Action for Grand Pianofortes (1875), in which the heads of the 

 hammers are reversed, and now face the wrest plank. 



Messrs. Wornum fy Sons. 



By this invention longer strings may be used, relatively to the external 

 dimensions, than in an instrument of the ordinary construction. 



750. Model of the action of Ancient Great Hydraulic 

 Organ, from Mr. Chappell's description of the instrument. 



Dr. Stone. 



751. Marimba or Balafo, from South-eastern Africa. 

 Modern. Given by Captain J. Stuart. 



South Kensington Museum. 



The instrument has twelve slabs of a sonorous wood, beneath which are 

 fastened, by means of a dark-coloured cement, twelve gourds, to increase the 

 sound. In each gourd are two holes, one of which is at the top, and the 

 other at the side. The latter is covered with a delicate film, to promote 

 the sonorousness. Several African travellers have noticed this curious 

 acoustic contrivance. Du Chaillu says that the film consists of the skin of a 

 spider ; Livingstone mentions spiders' web being applied to instruments of 

 this kind used by certain native tribes in Southern Africa. The marimba is 

 a favourite instrument of the negroes as well as of the Kafirs. 



752. Glass Harmonica. Modern. Made by E. Pohl, in 

 Bohemia. South Kensington Museum. 



The glass harmonica consists of a series of glass bells, which are affixed in 

 regular order to an iron spindle lying horizontally in a case, and which by 

 simple machinery are set in motion by the feet. The sound is produced by 

 the performer moistening his fingers and pressing them on the bells while 

 these are rotating. 



753. Sol- Fa Harmonicon, invented by Miss Glover. In- 

 tended as an assistance in learning singing, and the theory of 

 music. South Kensington Museum. 



754. Organ Pipes, a selection in illustration of their manu- 

 facture, showing the middle C pipe of each stop. H. Speedily. 



755. Chromatic Harmonium, peculiarly constructed key- 

 board, " showing the twenty-four progressions. The common 

 method is seen at the back of the instrument in connexion with the 

 keys." Mrs. Read. 



