LONDON, AND VOYAGE TO SINGAPORE 319 



rock surface, often containing several groups of forty or fifty- 

 distinct figures. It is rather curious that several of the groups 

 in my two plates do not appear in any of the twelve plates 

 of Count Stradelli. Besides these drawings there are several 

 large scale sketch-plans of the portions of the river where 

 they were found, mostly at cataracts or rapids where there 

 are large exposed rock surfaces. The map showing the first 

 three cataracts well illustrates the description of them given 

 at p. 197 of my " Travels." But besides these sketch-plans 

 there is a large folding map of the Uaupes, drawn by Count 

 Stradelli from " compass " bearings during this last journey. 

 There is no reference whatever to this map by the Count 

 himself, except the statement on the title that it is by " com- 

 pass " observations, as was mine. And as there is no refer- 

 ence to any determinations of longitude the distances could 

 only have been ascertained by estimated rates of canoe-travel, 

 such as I used myself. I therefore compared the two maps 

 with much interest, and found some discrepancies of consid- 

 erable amount. His map is on a scale rather more than four 

 times that of mine; but my original map, now in the posses- 

 sion of the Geographical Society, is on a larger scale than 

 his. His longitude of the river's mouth is 67 ° 5', mine being 

 68°, more accurate determinations having now been made 

 than were available at the time I prepared my map, more 

 than fifty years ago. On comparing the two maps we see 

 at once a very close agreement in the various curves, sharp 

 bends, loops, and other irregularities of the river's course, so 

 that, omitting the minuter details, the two correspond very 

 satisfactorily. But when we compare the total length of the 

 river to my furthest point, close to the mouth of the Codiary, 

 there is a large difference. The difference of the longitudes 

 of these two points on the Count's map is 2° 22', whereas on 

 mine it is 3 45'; my estimate being about 60 per cent, more 

 than his. By measuring carefully with compasses in lengths 

 of five miles, with a little allowance for the minuter bends, 

 his distance is 315 miles, mine 494, mine being thus 55 per 

 cent. more. 



It is unfortunate that Count Stradelli has given us no 



