LECTURES. 109 



enable US to know what has been done and what remains to be accom- 

 plished in this vast field of research. Plence it is evident that very 

 seldom, if ever, can we determine when an old map is really obsolete 

 and of" no further use at all. 



The work of surveying, exploring, and map-making, is, like every 

 other human pursuit, cajnible of an endless approximation towards 

 perfection. It is constantly progressive — particularly as regards this 

 new world, America. There is an inaccuracy of expression when we 

 speak of the discovery of America by Columbus. The great woik of 

 the discovery of America was only begun by Columbus ; it has been 

 going on for the last three centuries, and cannot yet be said to be 

 com[)leted. And, therefore, here especially an institution is wanted 

 the business of which shall be to follow and record step by step this 

 progress, and thus become a common fund and treasure-house of all 

 preceding an I contemporaneous discoveriPs. 



Truth and error are handed down together, from generation to gen- 

 eration, through the history of mankind. It is curious, that wliile 

 this is often admitted to be the iact as regards the history of other 

 sciences, geographers until now seem to have believed that it has no 

 application to chartography —a science which, according to them, like 

 the phoenix, each day is consumed and each day is born again from 

 its ashes ; but, to show how false this notion is, I may cite the state- 

 ments of the able author of the article on (xeography in the Encyclo- 

 paedia Britannica, who says that the tables and measurements of 

 Abulfeda and of Nazir Eddin, and the maps of the interior of Asia, 

 made under the enlightened Calif Almamoun, were, as late as the 

 year 1817 — that is to say, about 1,000 years afterwards — of use in the 

 construction of the maps of some parts of Asia. 



On the other hand, the longevity of errors in geography, and con- 

 sequently in maps, may be illustrated by the following instances: It 

 is well known that the great father of geography, Ptolemy of Alex- 

 andria, committed the extraordinary error of assigning to the Medi- 

 terranean sea a length of not Icbs than sixty-two degrees of longitude, 

 which was upwards of twenty degrees too much. This amazing 

 mistake affected all our ma[)s of the Mediterranean more or less until 

 the beginning of the last century. Many astronoTiiers and navigators 

 knew, long before that time, that the Mediterranean was actually 

 much shorter, and many map-makers ventured to cut oif a few de- 

 grees, despite the statement of the great Egyptian ; hut so absolute 

 was the authority which he enjoyed amongst Christians as well as 

 Arabians, that they were extremely slow in <ieviating from him, and 

 came down to the truth very unwillingly. In this instance tiie con- 

 test between truth and error lasted more than 1,500 years, until at 

 length the French geographer Delille gave to the sea its true limits. 

 But if such a thing could hafipen with resftect to the Mediterranean, 

 which from the beginning of commerce and civilization was the best 

 known part of the world, is it not highly prohaljle that we may dis- 

 cover similar longeval errors in such little known countries as, for 

 instance, the interior of Patagonia or Brazil ; and that, by studying 

 and comparing the maps, we may trace these errors to their source, 

 and so help to correct Lhem? 



