As noted above they are most likely accessory horns. In '39 on the cars they were called "Town & Country" horns with a switch on the top of the dash to switch between the single "Town" and double "Country" horns. The use a relay, powered straight off of the battery. One hot wire to each horn & the ground to the horn button (from memory, don't have a diagram in front of me). I have a set on my '38 coupe and wired a three position (on left-off-on right) toggle under the dash in place of the hard to find switch for the top of the dash.
Here's how mine looked pre restoration.

Last edited by Tiny; 05/19/2010 5:59 PM. Reason: added pic
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