1 10 LECTURES. 



Another equally remarkable though not so old an instance of the 

 long continuance of errors on maps, is presented to us in the works 

 of the great French geographer, Euache. He conceived the idea that 

 the whole surface of the earth was divided into certain principal and 

 lateral basins, each of which was surrounded by mountains, whilst its 

 central part was occupipd by a great lake or ocean, into which rivers 

 flowed on every side. This conception was, to some extent, true ; but 

 Buache carried it to an extreme, and, his head being full of this idea, 

 he drew on his, in other respects valuable, maps as many basins as 

 could in any way be brought into seeming harmony with ascertained 

 facts. A French savant says, in a work of the past year, that his 

 system still exercises a pernicious influence on the best French map- 

 makers, who, inheriting the theory of Buache, have continued to 

 propagate its fanciful deductions. 



The old maps, therefore, are not only precious for some hidden 

 treasure of truth which they may contain, but just as valuable for the 

 facility which a series of them afi'ords for tracing traditional errors. 

 "All maps," says a British geographer, "should be considered as 

 unfinished works, in which there will always be something to be cor- 

 rected or something to be inserted." 



Buache, Forster, La Condamine, Humboldt, and other enlightened 

 geographers, have shown how useful they considered the knowledge 

 of the opinions of former cosmographers, by taking the trouble to com- 

 pose what they called maps of errors. La Condamine composed a com- 

 jiarative map of the course of the Amazon river, on which he showed, 

 with different colors, how the direction and bends and branches of 

 this river were represented by different geographers. 



Buache and Forster made maps of the northwest coast of America, 

 on which they combined, in one picture, the outlines of that coast, as 

 they found them represented on the authority of a number of difi'erent 

 observers. 



Humboldt composed, with great care, a map of Mexico, with the 

 erroneous astronomical positions of many important points of that 

 country. Others have done the same for other parts of America. 

 But these so very useful and instructive maps of errors form a class of 

 scientific compositions which are not yet as much in use as they deserve 

 to be. They are probably so rare because there exist so few chrono- 

 logical collections of old maps. And this again proves how desirable, 

 how necessary, such collections are. We cannot dispense with them, 

 so long as we cannot say that every part of our maps is above all 

 criticism, and so long as the picture of the whole continent, in all its 

 parts, is not laid down with absolute and minute accuracy. Only 

 when this shall be the case, will we be justified in cutting loose our 

 connexion with the past ; then only can we cast overboard the whole 

 erroneous structure of our forefathers, or consign it at least to oar 

 collections of antiquity, as a mere matter of curiosity. 



V. — MAPS AS HISTORICAL DOCUMENTS, 



Historians, geographers, and travellers, have laid down on their 

 maps many things of which they have not spoken at all in their books. 



