Errors of Latitude. 239 



To trace Vizcaino's narrative I first followed his chart of Cali- 

 fornia as given b}^ Bnrney ; but have since obtained from the 

 State Department at Washington copies of the coast line, as 

 drawn from his thirty-two plans, by the navigators of the Sutil 

 and Mexicano, 1802, with all his names. This chart is of vari- 

 able scale and without parallels of latitude, but when these are 

 supplied through means of well recognized capes and harbors, it 

 is a remarkably good work for that period. 



The modern charts which have been consulted have all been 

 made by the United States Coast and Geodetic Survey, and the 

 coast pilots from San Jose del Cabo northward have been con- 

 suited for exactness of geographic position and for the views of 

 headlands. 



The Errors of their Lutrimients. 



As the investigation progressed it became evident that there 

 were large errors in the determinations of the latitude by Ca- 

 brillo and Ferrelo ; these and the erroneous estimates of dis- 

 tances were at first very confusing for the identification of capes 

 and harbors insufficiently described, and I had to rely upon my 

 personal knowledge of the coast and seaboard to locate them. 

 The navigators rarely gave the latitude nearer than half a de- 

 gree, but the effect orthis was not apparent at the outset, where 

 their reported measures were very nearly in accord with the 

 true positions. When I had established the large and constantly 

 increasing errors as the vessels sailed northward the identifi- 

 cation was much simplified. 



Tliere were several points on the coast of Mexico, and one or 

 more near the southern extremity of Lower California, whose 

 latitudes were doubtless known to all the navigators with a rea- 

 sonable decree of accuracy, and evidently accepted by Cabrillo 

 and Ferrelo. 



The latitude of Puerto cle Navidad, whence the San Salvado7' 

 and La Victoria sailed, is 19° 13' north, and quite naturally it is 

 not mentioned by either of the captains. Cape Corrientes, which 

 was well known, is distant thirty leagues from Navidad, in lati- 

 tude 20° 25', and although Ferrelo says they had a southeast 

 wind, and estimated the distance at forty leagues, Cabrillo places 

 the cape in latitude "twenty degrees and a half." At this time 

 I assume he did not observe, for the latitude, but adopted that 

 given by previous authorities. 



