This looks familiar but I can't place it. On eBay right now at
http://www.ebay.com/itm/MYSTERIOUS-ANTIQUE-WESTERN-ELECTRIC-TESTING-OR-TELEPHONE-DEVICE-OAK-BOX/132094668467
Seller description: "MYSTERIOUS, UNKNOWN ANTIQUE WESTERN ELECTRIC TESTING OR TELEPHONE DEVICE OAK BOX -- Curious antique, testing, telephone or other early electric device marked Western Electric. Dovetailed oak box measuring about 3 x 5 x 2.5 inches. Leather strap handle, two binding posts on top, with push-button switch. Inside appears to be a spot for a dry cell battery and electrics include what appears to possibly be a rotating flywheel attached to a spring. perhaps this unit generated some kind of oscillating signal or current---only a guess. We really don't know and presume the buyer will know what it is or otherwise be inclined to purchase it as we were---out of sheer curiosity! Inside shows some corrosion of one sort or another so definitely sold as untested and as-is."
used to buzz out pairs on cable