This apparatus proves a dramatic demonstration of the destructive effect of a lighting bolt striking a house through a defective lightning rod. The structure consists of a small wooden house made of hinged walls fitted with a brass rod representing a lightning rod. A section of the conductor runs along a wooden batten placed on the façade. Inside the house is a spark-gap arrangement set in a small brass cylinder containing some gunpowder.

When the batten is removed, the lightning-rod conductor is severed. The lightning, simulated by a spark generated by a Leyden jar, ignites the gunpowder. The resulting explosion causes the house to collapse. But if the wooden batten is positioned properly, the electricity will leak to ground, leaving the house intact.

In 1780, Filippo Lucci depicted a similar device in the Stanzino delle Matematiche at the Uffizi, clear evidence of the interest in such demonstrations in the late eighteenth century.