XXVi APPENDIX. 
Mr. Park's hearings and distances, and then to correct the bearings by his 
observed latitudes, as far as these extend : and beyond that, I have taken his 
bearing by compass, and al'owed the supposed quantity of variation* 
The result of these calculations, together with the addition of his line of 
distance from Sego to Tombuctoo, was then compared with the popular 
report of the distance between the several stations of Woolli, Fort St. Joseph, 
Bambouk, and Tombuctoo. It was found that these reports did not mate- 
rially differ from the aggregate distance given by Mr. Park; although they 
fell short of it; a difference which might naturally have been expected, 
and which I have ventured to alter. The difference, however, does not ex- 
ceed twenty-four geographic miles; a mere trifle in African geography. 
The position of Tombuctoo, so obtained, differs only half a degree in 
latitude, and still less in longitude, from that arising from the intersection of 
the lines of distance from Morocco on the N W, and Fezzan on the NE; 
of which a particular account will be given in the sequel. 
A great part of Mr, Park's geographical memorandums are totally lost: 
but fortunately his bearings by compass during a great part of the way, are 
preserved. In other parts, he has preserved only the calculation of latitude 
and longitude, arising from them; which, however, of course furnish the 
means of obtaining the bearings, if necessary. As he omitted to take obser- 
vations to determine the quantity of the variation of the compass, after he 
lost the means of correcting his course by observations of latitude, which 
was at Jarra, about midway in his route:* it becomes a question of some 
importance, what q^uantity to allow on those long lines of distance between 
Jarra and Silla; Silla and Manding. 
It appears on inquiry, that the quantity of variation is no more known, 
any where 'Within the continent Africa, than within that of New Holland. 
And it happens mo.reoyer, that the lines of equal quantities of vanation, da 
no.t run across Africia with that degree of regularity and parallelism, which 
takes place over great part of the Atlantic and Indian oceans (at least this 
is what appears clearly to my judgment) : so that it became necessary to 
inquire, what quantity prevails in the surrounding seas; and what the general 
* The places of observation are marked on the Map by asterisks. 
