THE TOPOGRAPHIC SURVEY OF MICHIGAN. 153 



many branches of knowlcMlgo they offer not only direct aid, but suggest 

 new methods and untrodden paths of researcli. 



To Engineers: Contour topographic maps supply such data to en- 

 gineers as is obtained frequently at great exi)ense, by means of prelimi- 

 nary surveys, such, for example, as are usually made for the trial loca- 

 tion of railroads, canals, irrigation systems, reservoir sites, aqueducts, 

 etc. : or in brief, for all engineering works in connection with which the 

 relief of the surface of the earth throughout a considerable and fre- 

 quently great extent of country needs to be known before the best loca- 

 tions for the far more expensive detailed surveys can be chosen. 



In reference to the direct money value to engineers, and to the com 

 panics, corporations, etc., employing them, of a contour topogi'aphic map 

 of Michigan, for example, it may be shown that with such a map in 

 hand, a railroad could be projected across the State, grades computed, 

 cuts and fills measured and approximate cost of construction ascertained 

 without expense for trial surveys. More than this, not only could one 

 such line be studied but all possible routes between any tAvo localities 

 within the State, discovered and scrutinized and from a comparison of 

 them the most desirable location chosen, for both engineering and com- 

 mercial reasons. All of this can be done with the aid of a creditable 

 contour topographic map, without the expenditure of a single dollar for 

 surveys. What has just been stated is equally true of ship and drainage 

 canals, trolley lines, telegraph and telephone lines, water supply and 

 sewer systems, or, in short, all geographically extended undertakings 

 that states, municipalities, companies, etc., commonly engage in. 



In what has just been stated, reference is made to savings that may be 

 secured by using a topographic map in place of preliminary surveys, but 

 as may be illustrated by many definite examples, contour topographic maps 

 are of service in suggesting wavs in which railroads, etc., alreadv con- 

 structed or for which final, detailed surveys have been made, can be 

 shortened or otherwise improved. 



In proof of the above, perhaps seemingly too sanguine assertions, a 

 few from many specific examples that are available may be of interest : 



In the summer of 1901, the Wabash Eailroad Company was locating 

 a railroad line from the Ohio river across Jefferson and Harrison coun- 

 ties, Ohio, to connect with the Wheeling and Lake Erie railroad ; and 

 during the same summer a contour topographic map of the region referred 

 to was being constructed by the United States Geological Survey. The 

 railroad surveys were completed, a location chosen, grades, cuts, etc., in- 

 cluding a tunnel, decided on, and contracts for construction entered into ; 

 when advance copies of the topographic map that was being made came 

 to hand. From an inspection of the map the possibility of a shorter 

 route, with equally favorable grades, and without the necessity of a 

 ttinnel, was discovered. The ncAv location was at once adopted, and re- 

 sulted in the saving of |80.000.00 in construction. This correction of a 

 detailed railroad survey, with the aid of a contour topographic map, was 

 niade possible by a study of the map itself, and without expense. 



Again, at Waterbury. Connecticut, after two sources of water supply 

 for the city had been surveyed at an expense of |10,000.00, a contour 

 topographic map of the region about the city, made by the United States 

 Geological Survey, was received by the engineer in charge, Mr. R. A. 

 Cairns, and from an inspection of it, a better source from which to obtain 

 water was discovered, and finally adopted. Not only was the new site 

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