32 JoiirJial of Travel and Natural History 



with certainty on a ricli harvest of new species, or important 

 varieties in any of the above-named classes. 



Having already stated that the climate of Pungo Andongo, con- 

 sidering its situation in equinoctial Africa, is healthy and congenial 

 to Europeans, it is right that I should point out to the newly-arrived 

 that the frequent and severe atmospheric changes, occurring often 

 in the space of a few hours, require particular precaution. Owing 

 to its elevated position, the rock circle, and also the Presidium 

 itself, are covered with fog from dawn till 9 or lo o'clock a.m.; 

 consequently during these hours it is damp and cold (in the spring 

 62° to 63°,'^ in the summer, 66° to 69° Fahrenheit). As soon as 

 the foggy clouds disappear, the temperature rises quickly, reach- 

 ing its maximum height about 2 o'clock p.m. (in the spring, 1857, 

 73° to 75°; in the summer, 75° to 79°). From thence it gradually 

 falls again until it reaches its minimum, about two hours before 

 sunrise. This course in the temperature is subject to exceptions 

 and irregularities, because on calm days, or when the horizon 

 is cloudless early in the morning, the perpendicular sunbeams 

 falling then sooner into the rock hollow, thereby altering and con- 

 siderably increasing the day's atmospheric temperature within a 

 very short time. This, however, occurs exceptionally, for I 

 observed, on a few rare occasions, the thermometer shewing in 

 Pungo Andongo, that is, in the Presidium itself, more than 80° 

 Fahrenheit. 



The countries surrounding the rock circle, more especially the 

 Cuanza valley, extending on the west and south-west, have, as 

 may be supposed, a much higher temperature. One of the 

 highest temperatures which I observed during my residence in 

 Angola, occurred on the banks of the Cuanza River, 5 miles 

 distant from the Presidium. There, in March 1857, the sand- 

 slates, close to the river, were glowing with heat, at noon, so 

 intensely, that they scalded the feet of my negro attendants, and 

 penetrated even the strong soles of my boots in a most sensible 

 manner. 



The reader having been made acquainted in the foregoing 

 sketch with the topograpical and general botanical relations of the 



* All my observations in temperature were made with one Parisian and two 

 English thermometers, which, previous to my journey, had been carefully 

 tested and compared with standard instniments, I have, therefore, reason to 

 believe that the results, and my data of temperature, as well as my hypso- 

 mctrical measurements with the same instruments, are entitled to confidence. 



