32 VOYAGE IN SEARCH 



failors to flay on fhore, keep them on board. 

 Nothing but the duty of the fhip could induce 

 the Captain to let them fet their foot on land. The 

 Commodore fully intended not to relax from this 

 rule, during all his {ration on the coafl of 

 Africa. 



The variation of the magnetic needle obferved 

 on board, and deduced from fixteen obfervations > 

 fourteen of which were by azimuths, and two by 

 eafterly amplitudes, was found to be i8 7' 7" 

 welt. 



The refult of two obfervations made on fhore 

 upon the flat roof of a houfe in the town, by 

 Citizen Bertrand, one of the aflronomers of the 

 expedition, was 2 1 33' weft. 



Another obfervation, made on the Mole, 

 with an azimuth compaft, gave 23 43' of weft 

 variation. So much difference, at fuch little 

 distances, probably arifes only from the quantity 

 of ferruginous fubitances diilribulcd unequally 

 in thefc volcanic mountains. 



From thefe obfervations, thofc which were 

 made on board fecm to infpire more confidence, 

 as they agree with the progreffive decreafe of 

 the variation obferved iince our departure from 

 Brcft, and with that which had for a long time 

 been obferved by many other navigators. 



The dip of the needle (this was a flat needle) 



was 





