044 



GEOLOGICAL SURVEY OF THE TERRITOEIES. 



twenty-one hundred miles long, starting from mean tide at Portland, 

 Me., and reaching New Orleans, La., with an error of —9.9 feet. 



If we join the N. Y. C. and L. S. & M. S. E. Es. with the line from 

 Chicago to New Orleans, we have a connected chain of railroad-levels, 

 eighteen hundred miles long, starting from mean tide in New York Bay 

 and ending at mean tide New Orleans, with an error of only —2.44 feet. 



Using the Pa. E. E. and P. F. W. & 0. E. E. for a through-connec- 

 tion in the same way between mean tide Earitan Bay and New Orleans 

 mean tide, a distance of about eighteen hundred miles, the levels reach 

 New Orleans with an error of — 4.61 feet. 



These results will give some idea of the accuracy of extended lines of 

 railroad-levels when ijroperly connected. 



ELEVATIOlf OF CINCINNATI CITY BASE, WHICH IS STANDAED LOW WATEE EN" 

 OHIO EIVEE, 62. 50FEET BELOW H. W. 1832. 





Feet. 



Various datum -planes. 



Elevation in feet 

 above mean sur- 

 face of Atlantic 

 Ocean. 



First determination. 



L. W. Ohio Eiver at Cincinnati, by Miami and Erie 

 Canal. 



133. 00 



Below Lake Erie 







573. 08 









440. 08 



Second determination. 

 Columbus, Ohio, by C. C. C. & I. E. E 



167. 33 



Above Cleveland directrix. 





575. 68 









743. 01 





307. 58 







Col. & S. and L. M. E. E. 





435. 43 



Third determination. 



Columbus, Ohio, depot track, by C. C. C. & I. from 



Cleveland directrix. 

 Athens, Ohio, junction of M. & C, by C. & H. V. E. E 







743. 01 



96.00 



Below Columbus depot 







647. 01 



L. W. at Cincinnati point, 62.5 feet below H. W. 1832, 

 _= city base, by M. & C. E. E. 



207. 00 









440. 01 



Fourth determination. 

 Dayton, by D. & M. E. E 



180.00 

 313. 00 



Above Lake Erie at Toledo. 





L. W. at Cincinnati, by C. H. & D. E. E 







573. 08 









440. 08 



- Fifth determination. 



L. W. Ohio Eiver at Parkersburgh, by report of a line 

 of levels run from Cincinnati to Parkersburgh, (not 

 the M. & C. E. E.) 





Above M. T. Baltimore 



do 



573. 50 





440. 00 



Final results. 

 L. W. in Ohio Eiver at Cincinnati, city directrix : 







440. 08 









435. 43 



(1) Third determination 







440. 01 



(1) Fourth determination 







440. 08 



(1) Fifth determination .„. 







440. 00 









439. 74 









439. 74 



(The first determination is given a weight of (10) be- 

 cause it is a canal -line. The second and third de- 

 terminations are well checked at Columbus by the 

 P. C. &. St. L. E. E. from Pittsburgh.) 







746. 00 



Columbus depot track 



3.80 









742. 20 











