I did not test it electrically but it appears quite fine with no damage noted - see my 12 detailed photos. The crank part seems to work nicely - when I turn the crank is slowly spins back into position. Extremely rare alarm bell for certain.
H Thau was listed as an electrician 1870's - 1890's era Brooklyn NY. The item "Antique Gamewell Type Brass Telegraph Alarm Bell H Thau 1885 Fire Doctor Police" is in sale since Friday, May 10, 2019. This item is in the category "Collectibles\Historical Memorabilia\Firefighting & Rescue\Alarms & Bells".
The seller is "spooknook" and is located in Weymouth, Massachusetts. This item can be shipped worldwide.