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2

Medium sized sewing needle magnetized and used

Sound produced with this needle not as loud as with the wire magnet, but still clear and distinct.

When pitch of sound corresponded to normal of needle sound reinforced.

Finer needle used, good sounds heard.

Arrangement responded to highest pitches obtained at least 1500 per second.

Proved: that small magnets would produce audible sounds with gear-wheel.

Remains to be ascertained if small amount of iron deposited upon line would affect it.

Sharp toothed edge turned upon a piece of brass, and plated with iron, made to test this.

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3

Wednesday June 1-1881

A medium sized sewing needle was then magnetized and inserted in the place of the one shown in diagram preceeding page.  
Sound produced with this not as loud as with the wire magnets, but was still quite clear and distinct.  When the pitch of the sound corresponded to the normal rate of the needle the sound was much reinforced. A finer needle was then substituted for the one last used, and still very good sounds were heard.  
The lathe was turned very rapidly and at least 1500 teeth passed the needle per second, but the arrangement responded to the highest pitches I could obtain.
It being thus proved that very small magnets would produce audible sounds with the gear-wheel it only remained to ascertain if the small amount of iron that would be deposited upon a line would be sufficient to affect it.  
To test this a sharp edge was turned upon a piece of brass - thus [[hand drawn arrow]] [[image - diagram of brass piece with Saw-teeth labeled]] and a lot of fine saw teeth cut upon it by means of a "milling tool" (used to roughen the edges of thumb screws.)

Noted by S.T. June 1-1881