The Dome and Lightning Rod


Protecting the State House From Lighting

The lightning rod on the dome of the State House is the largest 'Franklin' lightning rod ever attached to a public or private building in Benjamin Franklin's lifetime. It was constructed in accord with Franklin's recommendations and has served the State House and the dome well for more than two centuries, with only one recorded instance of damage caused by lightning. The lightning rod is of wrought iron painted to protect it from corrosion. It is 28' tall and 2.5" square at its maximum thickness.


The State House Lightning Rod: A Timeline

[Expand All]

  • 1773

      Chapter 32 Laws of 1773:

      "... to guard the said Stadt House as far as may be against any Accident from Lightning. Be it further enacted that the said Undertaker shall fix place and secure in the best manner an Iron Rod pointed with Silver or Gold of six feet at least above the Height of the Cupola of the said building and conducted at least six feet in the Ground ..."
  • 1775/09/07

      Maryland Gazette, September 7, 1775:

      "On Saturday night last we had a most violent storm from the north-east, which for several hours blew a mere hurricane, with heavy rain; the water rose three feet perpendicular above the common tide; a great quantity of the copper on the state-house was torn up, and the market-house blown down; the damage sustained in different parts of the province, we are told, is very considerable."
  • 1775/09/07

      Charles Wallace to Daniel of St. Thomas Jenifer, ca. November 1784:

      "The September Storm of 1775 blew off the roof, the building unavoidably lay open near the whole Winter, in consequence of which, the work of the upper Rooms which was entirely finished, was Totally destroyed.-- At another time lightning very much damaged the Dom, repairing of which cost much expense & loss of Time." When the lightning struck is not clear, but the next sentence describes events in 1777 which suggests that the lightning may have struck sometime between September of 1775 and 1777 when the British fleet appeared in the Bay.
  • 1786/03/10

      The General Assembly gave its implicit approval to commencing work on Joseph Clark's dome which was 'to be 'sixty foot Higer' then the old one.
  • 1787/08-1788/06/05

      Simon Retalick, is engaged in ironwork on the State House. While there is no account extant for the lightning rod, there are sufficient accounting entries for Retalick to encompass his forging and installing the rod. From one surviving account, it is clear that Retalick worked for 32 days beginning in July 1787 and ending on or about August 25, 1787 on "iron work" for the windows of the State House. Similar sums are paid him in January and June of 1788. Assuming the windows were secured while the dome, cupola, and acorn were under construction, it would seem likely that Retalick completed the lightning rod by the time of the January entry in the accounts, or by June at the latest.
  • 1788/06/09

      Charles Willson Peale's diary:

      "begun a Drawing of the Stadt-House from the entrance of Cornhill Street for the Circle before Breakfast, before 11 O Clock I made another outline of the Stadt-House from the NN/E back view."
  • 1788/07/14

      "Went with my Brother to his Ex:y doctor Franklins, my Intention was to enquire his opinion abut the effecacy of the Rods on the Stadt House at Annapolis, the Doctr was Ill & could not be seen -- then Visit Mr. Patterson & David Rittenhouse on same enquiry abut lighning rods. Mr. Rittenhouse being of oppinion that if the points are good and near anough the Building and part going into the ground so deep as to get into soft earth no danger is to be apprehended, but if the end could be put in water of a Well it would be best. Afternoon I wrote to Mr. Richmond Coll. Ramsey & Nicholas Brewer. ...
  • 1788/07/23

      George Washington's Diary:

      "Wednesday ... [Mount Vernon] the most violent storm ever known commenced at 1700 and continued for 9 hours. "The Maryland Gazette at Annapolis noted the greatest tide in memory with northeast winds which gradually veered to southeast, but no abrupt shift to southerly took place, to put the Maryland capital east of the track of the center. At Baltimore a violent storm from the east-northeast raged for 12 hours ...."