139 
of Edinburgh^ Session 1863 - 64 . 
There are subjects, however, in which scientific men and men of 
no science feel an equal interest — which must engage the attention 
of every person of common intelligence. 
Among these is the great step recently made in African geo- 
graphy — the discovery of the head of the Nile. No other geogra- 
phical discovery can ever compare with this. It is not the solution 
of a puzzle in the Geographical Society. It is removing the 
‘‘ Impossible ” — the very type of impossibilities — from our books. It 
is opening to the whole world the mystery which was a mystery 
even to the initiated. Poets have lost a topic ! What philosophers 
and historians guessed and speculated about, is now written down 
plain on the map. That is now clear which has been wondered at 
since men began to ask the meaning of anything. We have lost 
the oldest subject of curiosity in the world ! 
A grave, prosaic mind loses its equanimity, and gives way to the 
charm of romance at the thought of the veil being raised that 
has for so many thousands of years covered the head of the great 
mysterious river which was worshipped of old — not more for its 
beneficent overflowings, regular as the seasons, yet unaccountable, 
than because of its unknown, unapproachable source. 
I do not mean that the facts which our travellers have brought 
to light run counter to the conclusions of former geographers. On 
the contrary, I think the body of history on the one hand, the 
speculations of science on the other, had prepared the world for 
such a discovery. Glancing at the ancient, I mean the classical 
authorities, without arraying them before you, I may say that among 
innumerable fables and much unphilosophical reasoning, they 
almost concur in giving the Nile its source in a mighty lake — some 
say two immense lakes — fed by periodical rains, — fed also, say some, 
by subterraneous streams flowing from the west (these subterraneous 
rivers were favourites with the wonder-loving naturalists of old). 
This great lake was further believed to lie at the foot of lofty, snow- 
covered mountains, named the Mountains of the Moon. Herodotus 
indeed demurs to the snow. The Eeservoir Lakes become immea- 
surable marshes in some of the accounts. Indeed I should despair 
of producing a catena of witnesses for any single point of the state- 
ment ; but such as I have described was nearly the mind of ancient 
Greece and Eome, speaking on the information obtained in Egypt. 
