The Survey and Map of MassacJncsetts. 81 



tically the same thing, 1:62,500, The relief of the surface is 

 represented by the contour lines, or lines of equal elevation above 

 sea, traced at vertical intervals of 20 feet. ']"'hese contour lines, 

 which are becoming a common feature of modern maps, add an 

 additional element. They expresss quantitatively the third dimen- 

 sion of the country, viz : the elevation. An inspection of such 

 a map not only shows the horizontal location of points, but their 

 vertical location as well. It gives the elevations of all parts of 

 the country represented, above the sea. 



The map represents all streams of magnitude sufficient to find 

 place on the scale, and all bodies of water, as lakes, swamps, 

 marshes, etc. In the matter of culture, in which definition is 

 included all the works of man, it seemed desirable to represent 

 only such as are of a relatively permanent nature, and to exclude 

 temporary works, for the very apparent reason that if temporary 

 works were included, the map would be not only a constant sub- 

 ject for revision, but even in the intei'val between the survey and 

 the publication, the culture might change to a large extent, and 

 the published map be correspondingly incorrect from the outset. 

 In searching for a criterion which could be consistently followed 

 in distinguishing between culture which should and should not 

 be represented, it was found that by limiting the representation 

 to that which may be denominated public culture, that is, that 

 which has relation to communities, as distinguished from individ- 

 uals, a consistent line could be drawn. Adopting this criterion, 

 the map contains all towns, cities, villages, post offices, — in short, 

 all settlements of any magnitude, all railroads and all roads, with 

 the exception of such as are merely private ways, all public 

 canals, tunnels, bridges, ferries and dams. There were excluded 

 under this ruling isolated houses, private roads, fences and the 

 various kinds of crops, etc. Forest areas are shown. Subse- 

 quently, however, in response to the urgent wish of the commis- 

 sioners, the survey consented to locate the houses upon the maps, 

 although in the engraving these have been omitted. The omis- 

 sion of all private culture leaves the maps very simple and easy 

 to interpret. For convenience the field work was done upon 

 a larger scale than that upon which the maps were to be pub- 

 lished, viz : a scale of 1 : 30,000, or a little more than double the 

 publication scale. The map of the state as planned is com- 

 prised in 52 atlas sheets, each of which comprises 15 minutes of 

 latitude by 15 minutes of longitude and an area of about 225 



