What happened on August 19, 1839?

From the text:

Lieutenant Peyton, as he recalled it, had run out of salt in the second year. He found an entry, dated August 19, 1839:

"The supply boat from Cow's Ford being much overdue, and my command lacking salt and suffering greatly from the heat, on 6 August I dispatched my loyal Creek guide, Billy Longnose, down the St. Johns (sometimes called River May) to discover the cause of delay. Today he returned with the information that our supply boat, beating its way upstream, had put into dock at Mandarin (a town named to honor the oriental nation from which it imported its orange trees). By ill luck, on that night the Seminoles raided Mandarin, putting to death a number of its inhabitants and burning the houses. The master of the supply boat, a civilian, and his crew, consisting of a white man and two Slaves, escaped to the woods and later reached St. Augustine. However, the boat was pillaged and then burned.

All other privations my men can endure except lack of water and lack of salt."