170 SEC. 6. SOUND. 



e. Four open and four stopped Labral Pipes, with small wind chest and 



valves, producing the C major accord : c : e : y : c. 



8:10:12:16 



f. Accord Reed Pipe, producing the C major accord c : e : g : c : e : y \ c. 

 (The two apparatus e and/ are for demonstrating the quality of Bound.) 



786. A Stand of Apparatus illustrating the 

 progress of ./Eolian Principles. 



J. Baillie Hamilton. 



1. Primitive ^Eolian types. 



The rod. 

 The bow. 

 The harp. 



2. Modern JEolian harp. 



3. Wind concentrated upon a string, and applied to its entire 

 length. By Professor Robinson. 



4. Wind applied to a portion of the string, as by Wheat stone, 

 Green, Isoard, &c. 



5. Further modifications of the same. 



6. Use of a free-reed. By Pape. The connexion with the 

 string being effected by a silk thread. 



7. Julian's mode. A metal string flattened into a tongue at the 

 part where the wind impinges. 



8. Farmer's mode. A reed-tongue substituted for the flattened 

 portion. 



9. Farmer and Hamilton's mode. A rigid connexion between 

 reed-tongue and string allows the reed to be used as in reed- 

 organs. 



SUBSEQUENT INVESTIGATIONS BY HAMILTON IN CONJUNCTION 

 WITH HERMANN SMITH. 



10. Improved string-organ note, in which a sympathetic re- 

 sistance is offered to the string, the vibration transmitted to the 

 soundboard, and constancy of pitch preserved by a spring-bow. 

 The reed tone is modified by a tube, and the connexion effected 

 through the tube by. a "purse," the latter suggested by Hermann 

 Smith. 



11. Further modification by Hamilton. The necessity for the 

 " purse " abolished by setting both reed and string inside the 

 register. The economy of space effected by Hamilton's spiral 

 spring, and the use of a short metal spring-bow. 



12. Application of these improvements for use in a wind- 

 viol. Also a conical string, invented by Hamilton, for obviating the 

 following difficulties peculiar to reeds and strings in combination. 



a. The difficulty caused by the string breaking into segments, 

 owing to the constraint on the reed, and the scarcity of 

 notes obtainable. 



