186 Course and probable Termmation of the Niger. [Aug. 



Ptolemy lays down the Libyan Lake in 35° E. 



This, deducting 25 degrees, to reduce it from Ptolemy's 

 longitude, would place the lake in longitude east of 



Greenwich 10°. 



But Major Rennell has placed it east of Greenwich in . 22°. 

 differing from Ptolemy no less than twelve degrees : and, if we suppose 

 Ptolemy's longitude drawn through Ferro, differing from him five degrees. 

 In my map, in which I have most scrupulously adhered to Ptolemy, the 

 Libyan lake is 13 degrees of longitude from the Geir — whereas Major Rennell 

 in his map makes it only 6 degrees — giving a relative difference of 7 degrees. 



" Major Rennell lays down the Chelonidae in 24° N. latitude, but Ptolemy 

 says they are in 20° N. In short, here, as in other maps, Ptolemy is made to 

 bend to the map, instead of the map being made strictly after Ptolemy, whose 

 name however is attached to these errors." 



So far the detection of the foregoing errors by the Lieutenant-General 

 is highly creditable to his laborious researches — literary and geographical. 

 But in a previous part of our author's dissertation (throughout which no 

 opportunity is neglected to indicate the great mistake into which alt 

 Ptolemy's map-makers have fallen, in making Ferro his Jirst meridian), 

 he tells us that " Lake Dumboo," which, by most authorities, is admitted 

 to be one and the same with Ptolemy's Chelonid8e,t " is laid down in the 

 map generally, in longitude 22 deg. east of Greenwich — a discrepancy," 

 Sir Rufane adds, " by no means sufficiently great to destroy the identity 

 of Ptolemy's two lakes of Chelonidae." 



Now, if by mistaking his first meridian, all Ptolemy's map-makers 

 are, by the Lieut.-General's discovery seven degrees in error, a corres- 

 ponding difference throughout every Ptolemaean map surely should 

 exist; and, therefore, this discrepancy which our author thinks too 

 inconsiderable to destroy the identity of Ptolemy's lakes, ought, to be in 

 keeping with Sir R.'s reckoning, to differ ^ve degrees instead of two. 

 But it has been well observed, that when once the mind is intoxicated 

 with a theory, it eagerly grasps at every shadow of evidence which 

 seems to favour it, and is frequently the first dupe to the system it has 

 created. 



On the subject of auricular evidence. Sir Rufane thus interrogates the 

 reader : — 



" Is not the greater part of the information we have relative to Africa 

 ' hearsay evidence ?' — from the time of Herodotus, who gave hearsay evi- 

 dence from King Etearchus, and so many others ; from the time of Pliny, who 

 took hearsay evidence from King Juba's accounts, down to Park, Denham, 

 and Clapperton, who have given us a great deal of hearsay evidence for what 

 they relate ?" 



Coming, as this interrogation does, from our intelligent author, we 

 cannot but express our surprise, that when it suits his purpose to support 

 his hypothesis, he lends so credulous an ear to auricular evidence. 

 Indeed, the ocular testimony of both ancient and modern chscoverers, 

 is quite overbalanced by the hearsay evidence, collected by recent tra- 

 vellers. Clapperton was led astray, and grossly deceived by Bello — 

 Laing was suspected to be a spy, and treacherously murdered. Lander, 

 when, as he imagined, (and Avhich we do not think to be altogether 

 improbable) he was on the right road to trace into the Atlantic a termin- 



* Sir Rufane observes, that " the plural used by Ptolemy, referred perhaps rather to the 

 tortoises which frequented the Lake, than to the Lakes, or Lake itself — for there is but 

 one."_P. 65. 



