302 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



prevent the destruction of forests in this region, which may- 

 be accomplished by the state itself becoming proprietor of 

 the greater portion of the territory, and setting it apart as a 

 public park as a summer reserve, in fact, for the feeding of 

 the canal system of New York. We might then witness 

 the astonishing spectacle of a wilderness agriculturally 

 worthless becoming the arbiter of empire, and by its won- 

 derful hydraulic facilities and fortunate location giving to 

 the State of New York, to a considerable extent, the con- 

 trol of the commercial destinies of the great West, the Can- 

 adas, and New England. Colvirts Survey of the Acliron- 

 clacks. 



CORRECTION OF LEVELS. 



The officers of the Army Signal-office, as also of our pub- 

 lic surveys, have daily need of accurate determinations of 

 the altitudes of points in the interior of the country. To 

 this end both the Coast Survey and the Smithsonian Insti- 

 tution have for many years been collecting the statistics of 

 levelings made by railroad engineers, and all of these col- 

 lections have been quadrupled in extent by the labors of the 

 Army Signal-office. In addition to the extensive examina- 

 tions given to this mass of material by the Weather Bureau, 

 Mr. Gardner, the geographer to the Geological Survey of 

 the Territories, under the Department of the Interior, has 

 made an exhaustive analysis of the altitudes along certain 

 lines of railroad, all leading to Denver, Colorado, his object 

 being to determine the elevation of that point by as many 

 independent lines of level as possible. In the course of his 

 work very many illustrations show the great accuracy that 

 can be attained by careful study, with good engineering in- 

 struments. He states, in effect, that of the innumerable dis- 

 cordances that occur, by far the greater portion are traced 

 to errors of calculation, and not to instrumental defects or 

 errors of observation. He establishes with great apparent 

 probability some important changes in the accepted levels 

 of points in this country. Thus the great lakes and sur- 

 rounding country are found to be about nine feet, and St. 

 Louis about twenty-three feet, higher than hitherto accept- 

 ed. Kansas City and the surrounding country for many 

 hundred miles south and west has heretofore been reported 



