Though Herrera's account of Ponce de Leon's first voyage is brief, it contains many clues which merit close examination.

Researches generally start with the latitudes recorded by Herrera because these, if accurately cast, would be exact. We must keep in mind, of course, the crude sighting instruments of the time and the unknown degree of skill used in their manipulation.

Herrera lists five specific latitudes for Florida: 30°8', 28°15', 27°, 26°30' and 26°15'. Unfortunately the only two that can be associated reliably with known landmarks are so much in error that all are suspect. Nevertheless, great effort has been spent in trying to find a pattern in the sightings.

An analysis of Ponce's landfall latitude of 30°8' was made by Capt. William Peters, of the Carnegie Institution, Washington D.C., at the re-quest of researcher Edward Lawson. The detailed calculations were reported in Lawson's "First Voyage of Ponce de Leon."

Precise navigation depends in large part upon the accuracy of marine almanacs. Two such are known to have been in existence in 1513: the "Regiomontanus" and the "Alphonso." The Regio was prepared in 1452 to correct the Alphonso and was itself revised in 1474. Ponce likely used the latest figures.

Neither almanac benefitted from astronomical observations made from the New World. According to Capt. Peters, the Regio entry for solar declination at north Florida for April 2, 1513, is in error by 9 minutes (9 nautical miles) too far north. Herrera's adjusted landfall latitude by this calculation, therefore, would be 29°59'. An adjustment of the landfall latitude by the Alphonso error of 1° would place Ponce near the inlet originally called Mosquito (as on the Cantino Map of 1502?) but renamed for the explorer comparatively recently.

Lawson concludes from Peters' work that Ponce spotted land five miles north of St. Augustine and then coasted to that harbor at

latitude 29°55'. Historian T. Frederick Davis con-curs. David O. True and other authorities contend Ponce came ashore below St. Augustine -- citing such things as compass headings, landmark descriptions and the long search southward for a harbor.

The latitudes of Herrera which we can associate reliably with known landmarks are 28°15' for the Cape of Currents, and 26°15' fοr the western end of the Keys.

The Cape of Currents is equated by Herrera to the Cape of Florida, which at his writing 88 years later was fixed at Key Biscayne. However his description of the cape's strong offshore flow and the mainland's eastward trend is conclusive evidence that the Cape of Florida meant by Ponce is today's Palm Beach.

The Gulf Stream flows strongest, and closest to shore, from Miami Beach to Palm Beach -- as was vividly impressed upon your author during a World War II enemy submarine chase in the "alley" within view of city lights.

Actual latitude for Key Biscayne if 25°40', and for Palm Beach is 26°35'. Thus, Herrera's figure for Cape Florida is too high by 2°35' or 1°40', respectively. The two white islands described by Herrera -- whether Boca Chica, Key West, Marquesas or Dry Tortugas -- lie in 24°32'. Herrera's figure here is 1°43' too high.

As we can see, the amount of error in Herrera's latitudes for the two recognizable land-marks is not consistent but averages on the high side by nearly one and a half degrees. If this large error is deducted from Herrera's landfall figure, the resulting location would be impossibly south of Cape Canaveral. Even Capt. Peters' small correction would not make Herrera's latitudes believable.

Sadly we must dismiss Herrera's navigation information from serious consideration. It is likely he interpolated old, inaccurate sources with a map of his day; and the landmarks are not related to actual sightings.