Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2- Appendix): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

270 APPENDIX. in the evening light winds come off the land, and continue till sun- rise; when it again becomes calm until the sea-breeze sets in as before. During winter (from April to August) light northerly winds may be frequently expected, accompanied by thick fogs, or dark lowering weather ; but this seldom occurs in the summer months, although even then the tops of hiUs are frequently enveloped in mist. To the northward of Callao, the winds are more to be depended on ; the sea-breeze sets in with greater regularity, and fresher than on the southern parts ; and near the limit of the Peruvian territory (about Payta and off Cape Blanco), a double-reefed topsail breeze is not uncommon. It is to be remarked, and may be laid doMia as a general rule, that although such moderate winds blow on the coast of Peru, yet sudden and heavy gusts come over high land after the sea-breeze sets in, which, from the smallness of the ports, may be attended with some inconvenience, if precautions are not taken in shortening sail previous to entering them. The only difference between winter and summer, as far as regards the winds, is the frequency of light northerly airs during the former months ; but in the state of the weather, the difference is far greater than one would imagine in so low a latitude. In the summer the weather is dehghtfully line, with the thermometer (Fahrenheit's) seldom below 70°, and often as high as 80°, in a vessel's cabin ; but during winter the air is raw and damp, with thick fogs and a cloudy overcast sky. Cloth clothing is then necessary for the security of health ; whereas in summer the lighter you are clad, the more con- ducive to comfort and health. The general set of the Current on the coast of Peru is along the shore to the northward, from half a knot to one knot an hour ; but occasionally it sets to the southward, with equal or even greater strength. The period at which these southerly sets take place cannot be ascer- tained with any degree of certainty. Neither seasons, the state of the moon, nor other causes common on almost every coast, seem to have an influence here. The oldest navigators, and men accus- tomed to the coasting trade, can assign no reason for these changes they only know that they do take place, and endeavour to profit by them accordingly.