Chap. XXVII. WE REACH THE MUKUKU-MADSE. 567 



eventually proved himself very useful as a guide. He after- 

 wards explained that he had been smoking hemp, and had 

 been excited to this mad sort of conduct. 



"We had now thunder every afternoon ; but while occasional 

 showers seemed to fall at different parts, none fell on us. The 

 air was deliciously clear, and revealed all the landscape co- 

 vered everywhere with forest, and bounded by beautiful moun- 

 tains. On the 31st October we reached the Mukuru-Madse, 

 after having travelled 660 geographical miles, or 760 English 

 miles in a straight line. This was accomplished in fifty-five 

 travelling days, twelve miles per diem on an average. If the 

 numerous bendings and windings, and ups and downs of the 

 paths could have been measured too, the distance would have 

 been found at least fifteen miles a day. A pedometer 

 showed more, • but in coming back from one short trip we 

 found that the instrument varied so much that we did not 

 use it again. A very good chronometer was employed to 

 measure the differences of longitude. It was carried in a box 

 of clothing, on the head of a man of steady gait. In order 

 to secure a chronometer being of any use, no dependence 

 ought to be placed on its rate, when stationary. Its travelling 

 rate must be ascertained by taking a series of altitudes of 

 the sun or stars at certain spots in the outward journey ; 

 and a second series of observations must be made at the same 

 stations in the return journey. By this means the exact 

 travelling rate can be found. The same plan should be 

 followed in a boat ; for, if this or some similar precaution be 

 not taken, a chronometer when carried is of little value in 

 measuring distances. This will be evident when it is men- 

 tioned that the chronometer we used, when at the ship, 

 had the rate — 11 s ; in travelling -f- I s daily, which would 

 amount to a daily error of three miles. 



The night we slept at the Mukuru-Madse, it thundered 



