298 OBSERVATIONS AT SALLEOLOOKIT. [1845. 



observations at Samboangan gave the dip of the Mag- 

 netic Needle northerly, and those at Sooloo nearly an 

 equal quantity southerly, it was highly important that we 

 should take advantage of every available spot of terra 

 firma included within those positions, to determine, ap- 

 proximately at least, the Zero curve. Independent of 

 this, our friends in the French squadron had informed 

 us, that they doubted the correctness of the Longitude 

 of the Duo Bolod Islets, which they considered to be 

 about fifteen miles in error. This position on Salleolookit 

 offered the means of approximating this point very satis- 

 factorily, as the bearings were very little to the eastward 

 of south. Our observations place this rock in Lat. 6 40' 

 52" N. Long. 121 24' 30" E. Dip. IT 30" Var. 

 17' 20" E., and by the bearings and assumed Longitude 

 of Sooloo, we found no reasons to suspect it to be out 

 in relative position. 



On the 28th we succeeded in crossing the stream 

 which sets strongly through the Straits of Basilan, and 

 fetched in with the land about twenty miles to the north- 

 ward of Calderas, when by making short tacks along the 

 western coast of Mindanao we succeeded in making 

 better progress. 



On the 28th March, we stood off to seek the Caga- 

 yanes Group, about which we had received very con- 

 flicting accounts, and about nine, A.M., of the following 

 day effected a landing on a small rocky islet, situated in 

 the channel between the two largest islands. A rapid 

 survey was made during our short detention of six hours, 

 by which we discovered that neither the Charts nor the 

 sailing directions, by Horsburgh, afford any correct in- 



