EFFECT OF RAINS. 351 



with trees. We crossed the river Nackachinta, flowing 

 westward into the Kafue, and then passed over ridges of 

 rocks of the same mica schist which we found so abundant 

 in Golungo Alto : here they were surmounted by reddish 

 porphyry and finely-laminated feldspathic grit with trap. 



As we passed along, the people continued to supply us 

 with food in great abundance. They had by some means 

 or other got a knowledge that I carried medicine, and, 

 somewhat to the disgust of my men, who wished to keep 

 it all to themselves, brought their sick children for cure. 

 Some of them I found had hooping-cough, which is one of 

 the few epidemics that range through this country. 



CHAPTEK XXVIII. 



DR. LIVINGSTONE DESCENDS THE ZAMBESI RIVER TO ITS CON- 

 FLUENCE WITH THE LOANGWA. 



13th. — The country is becoming very beautiful, and fur- 

 rowed by deep valleys; the underlying rocks, being igneous, 

 have yielded fertile soil. There is great abundance of large 

 game. The buffaloes select open spots, and often eminences, 

 as standing-places through the day. We crossed the Mbai, 

 and found in its bed rocks of pink marble. Some little 

 hills near it are capped by marble of beautiful whiteness, 

 the underlying rock being igneous. Violent showers occur 

 frequently on the hills, and cause such sudden sweeping floods 

 in these rivulets that five of our men, who had gone to the 

 other side for firewood, were obliged to swim back. The 

 temperature of the air is lowered considerably by the daily 

 rains. Several times the thermometer at sunrise has been 

 as low as 68°, and 74° at sunset. Generally, however, it 

 stood at from 72° to 74° at sunrise, 90° to 96° at midday, and 



