134 LECTURES. 



special maps of small territories at all; and for some, probably, we 

 never shall possess them. Many natural features seem to sweep with 

 a certain uniformity over a large tract of country ; so that nobody has 

 ever thought of giving us a special wind map of the State of Dela- 

 ware or a zoological map of Long Island. 



It is true that even in these extensive natural phenomena, which we 

 now portray only with a broad brush, we may, in time, discover some 

 regular local peculiarities worthy of being delineated on a map. In 

 some cases we have already discovered such local variations. Recent 

 observations have shown, for instance, that the deviations of magnet- 

 ical attraction^ even on such a circumscribed territory as the District 

 of Columbia, are very great ; and we may, in time, possess special 

 magnetical maps of the District and of similar small localities. 

 Modern observers again have shown how very peculiar and exceptional 

 are the movements of the great tidal wave in such a small Avater basin 

 as the Sound of Long Island, and they have tried to paint these pe- 

 culiarities on a special tidal map of the Sound. Cases like these, 

 however, are too exceptional to justify the adoption of such a ])lan. 



For the present, therefore, we jH-opose that all tlie so-called physical 

 maps, to whatever science they may belong, shall be thrown into one 

 and the same great division under the general head of physical mops, 

 and that this division shall, for further convenience, only be subdi- 

 vided into those twenty-one great divisions into which we have divided 

 our topographical and political maps — that is to say into general 

 physical maps of the whole of America, and then into physical :iiaps 

 of the Mississippi valley, Mexico^ Brazil, Patagonia, &c. &c. To 

 these twenty-one divisions we may then add five or six divisions for 

 the physical maps of the American seas, which have found no place 

 in the topographical collection, one for the Atlantic ocean, one for the 

 Mexican Gulf, a third for the Pacific, and a fourth and fifth for the 

 Arctic and Antarctic oceans. 



There are still many other classes of maps, which we cannot well 

 classify under the head either of topographical and political or of 

 physical maps, or which,' at least, we are not accustomed to consider 

 as a part of either. 



First, there are the ethnographical maps, pretty numerous in this 

 country, where so many different native tribes are found. The 

 names and localities of these tribes and of different other nations have 

 often been put down on the general topographical maps ; and thus 

 ethnography is, to a considerable extent, included in those maps. 

 But in modern times maps have been constructed whose especial object 

 is ethnography, or the distribution of tribes and languages. 



There are, also, the so-called moral maps, which exhibit tlie sta- 

 tistics of crime or of certain customs ; others again try to give us 

 the statistics and limits of the various diseases and other phenomena 

 among men. Some show the denseness of population in the different 

 parts of the country. We may comprehend all these under the 

 general name of statistical maps. Some geographers, as, for instance, 

 Berghaus and Johnston, have incorporated these ethnographical and 

 statistical maps in their atlases and collections of physical maps. 

 But it is evident that they do not properly belong there. 



