54 NOTES OF A NATURALIST. 



to Callao, without touching at that or any of the 

 smaller places on the coast sometimes visited by the 

 steamers. Although the air appeared to be somewhat 

 hazy, the range of the Cordillera, more than a hun- 

 dred miles distant, was distinctly seen in the after- 

 noon. Very soon after we ran into a dense bank of 

 fog, in which we were immersed for several hours, our 

 cautious captain remaining meanwhile on the bridge, 

 and the frequent cry of the steam-whistle ceased only 

 when we steamed out of the fog into a brilliant star-lit 

 night. 



These fogs, which are frequent along the Peruvian 

 coast, are the chief, if not the only, difficulty with 

 which the navigator has to contend. When they rest 

 over the land it becomes extremely difficult to make 

 the ports, and at sea they involve the possible risk of 

 collision. If this risk is at present but slight, it must 

 become more serious when intercourse increases, as it 

 must inevitably do if the Ship Canal should ever be 

 completed ; and for the general safety it may be 

 expedient to prescribe special rules as to the course 

 to be taken by vessels proceeding north or south 

 along the coast. The origin of the fogs must be 

 obvious to any one who considers the physical con- 

 ditions of this region, to which I have already referred. 

 The air must be very frequently near the point of 

 saturation, and a slight fall of temperature, or the 

 local intermixture of a body of moister air, must 

 suffice to produce fog. The remarkable thing is that 

 this should so very rarely undergo the further change 

 requisite to cause rain. To some young Englishmen 

 on board, the remarkable coolness of the air along 



