940 



Popular Science Monthly 



A Musical Electric Door- Bell 



AN unusual door-bell, differing from 

 the noisy regular electric bell, is 

 here described. This apparatus may- 

 look unpractical and clumsy, but it 

 can be covered up in a neat wooden case, 

 if desired. Procure a small instrument 

 commonly known as the "tubaphone." 



drilled in the upper end of the strip 

 serves to admit a screw holding a 

 wooden hammer-head. A small strip 

 of felt is glued to each striking side of 

 the block. These proceedings, as de- 

 scribed, are carried out for the other 

 strips, hammers, etc., along the appara-. 

 tus. Another piece of brass is fastened to 



A tubaphone consists of a wooden rack each of the long hammers to act as a trip. 



on which are mounted 

 several pieces of brass 

 tubing cut into different 

 lengths, and properly 

 tuned to give forth the 

 various notes of the 

 scale, when set in vibra- 

 tion. Such instruments 

 are usually sold at fifty 

 cents, the price depend- 

 ing upon the size, etc. 

 Several strips of pine 

 about 2 ins. wide, and 

 7/8 in. thick are pro- 

 cured to be used in the 

 framework. It is simple 

 to make, and is readily 

 understood by examin- 

 ing the diagram. 



The tubes are sus- 

 pended, as shown, on 

 rings or rubber bands. 

 The distance between 

 the tubes should be at 

 least one inch ; the first 

 and last tubes must also 

 be about one inch from 

 the edge of the frame- 

 work, for placing a 

 support on each side. 

 The base luay be of any size desired, 

 but these dimensions can only be 

 determined by calculation, and upon 

 the number of brass tubes used, etc. 

 A roller should be turned out from 

 a piece of pine, long enough, of course, 

 to be within the range of every hammer 

 striking the brass tubes. A shafting 

 attachment on the roller is also to be 

 provided for. 



Lastly, the hammers are made of 

 sheet brass, having a length that will 

 reach from the base of the apparatus, 

 to a point slightly above the bottom of 

 the suspended tubes. A hole is drilled 

 in the bottom end of each strip, which 

 is firmly fastened to the base by a 

 round-headed wooden screw. The hole 



I^OOOEM 

 FRAMEWORK 



It is riveted to the ham- 

 mer so that its upper end 

 will come in touch every 

 now and then with the 

 wooden pegs, fastened on 

 the revolving-roller. The 

 setting of the pegs in the 

 roller requires some pa- 

 tience; one mistake will 

 be of more value than an 

 hour's description. The 

 pegs, which are obtained 

 from a shoemaker, must 

 be set so that the music 

 will sound cor- 

 rect, care being 

 taken that the 

 higher tubes vi- 

 brate in sym- 

 pathy with the 

 lower notes. 

 With an ordi- 

 nary motor and 

 push-button, 

 with the con- 

 nections de- 

 picted, the ar- 

 rangement will 

 be found com- 

 plete. 

 As soon as the button is pressed, the 

 motor will revolve, and, being shafted 

 on to the roller, will rotate it. The 

 pegs will actuate the hammers, and the 

 hammers will in turn vibrate the brass 

 tubes, producing the musical strains, 

 which show that someone is at the door. 

 Such melodies as "Home Sweet Home," 

 may be made and if the folks tire of 

 the same tunes, several rollers may be 

 on hand and changed as often as desired. 



Antenna Wire Strength 



PHOSPHOR bronze antenna wire is 

 practically as strong, for the same 

 cross-section, as the best iron. This is 

 nearly twice the strength of copper and 

 over four times that of aluminum. 



The mere pushing of a button at the door 

 causes this apparatus to play a tune 



