234 ANNUAL KECOED OF SCIENCE AND INDUSTRY. 



sources of error. The whole lake region is changed by the 

 same amount as the lakes. 



The following are some of his results: 



Feet. 



The Cincinnati City Directrix 439. 74 



Pittsburgh, Main Depot track 74().00 



Harrisburg, Pa. , Raih-oad Depot track 319.91 



Philadelphia, City datum 8.73 



Albany, mean tide in river 4.84 



Lake Champlain 100.84 



Lake Ontario, mean surface 250.00 



Indianapolis, Main Depot track 721.75 



Cairo, city base of levels 291.23 



St. Louis, City Directrix 428.29 



Chicago, City Directrix 587.15 



Rock Island, C. R. I. and P. Depot track 568.68 



Burlington, Iowa, Main Street Depot 531.61 



Omaha, top of abutments of railroad bridge 1,049.40 



Kansas City, mark of high water of J 844 770. 77 



Denver, K. P. R. R. Depot track 5,196.58 



Cheyenne, U. P. Depot track 6,075. 28 



Pike's Peak 14, 146.68 



Mount Lincoln 14,296.66 



These heights are largely different from previous estimates. 

 Our great railway centres and entire states are raised 10 to 

 115 feet in altitude. The whole of some parts of the conti- 

 nent seems to be much higher above the sea than was sup- 

 posed. One of the most interesting results of the investiga- 

 tion is that it shows our American railroad levels to be very 

 accurate when long lines are considered. The New York 

 Central and Lake Shore and Michis^an Southern Railroads 

 joined with the Illinois Central and Southern Railroads to 

 New Orleans make a continuous line of levels 1800 miles 

 long from New York Bay. They reach the Gulf of Mexico 

 with an error of only two and a half feet. The two great in- 

 dependent lines the Union Pacific and the Kansas Pacific 

 Railroads reach Denver with a difference of only five feet. 

 Such accuracy in American leveling speaks well for our en- 

 gineers. The careful determination of altitudes of high and 

 low water at a number of points on the Ohio, Mississippi, 

 and Missouri Rivers is one of the most important contribu- 

 tions, establishing, as it does, the true fall of these rivers at 

 different stages of water a subject of which our previous 

 knowledge was very inaccurate. Mr. Gardner closes with a 



