What is the effect on an agency contract if the subject matter of the agency is destroyed?

Primary text

The agency contract is voided if the specific item (al-'ayn) over which the agent was granted authority to dispose is destroyed, because its subject matter is gone. This is analogous to revoking the agency when an agent authorized to sell a slave finds that the slave has died. If an agent is given money specifically to purchase something, and that specific money perishes or is lost, the agency is voided, irrespective of whether the agent was authorized to buy a specific item or generally to buy with that money. If the money perished, the purchase with it becomes impossible. Furthermore, if the purchase were valid, the principal would be bound to an expense they did not agree to be liable for.