Note 41 — Chapter IX
Reading edition
Dr. Livingstone observed that traders generally traveled ten days in the month, and rested twenty, making seven geographical miles a day, or seventy per month. In his case in this journey the proportion was generally reversed--twenty days of traveling and ten of rest, and his rate per day was about ten geographical miles, or two hundred per month. As he often zigzagged, the geographical mile represented considerably, more. See letter to Royal Geographical Society, October 16, 1855.