INDUSTRIAL PROGRESS DURING THE YEAR 1874. lxxvii 



of the Colorado. A second base for reference in Dr. Hay- 

 den's surveys has also been measured under the direction of 

 Mr. Gardner. 



Several works have lately been published giving the alti- 

 tudes of various points throughout the United States. One 

 of these belongs to the series of reports of Professor Hayden's 

 survey, referring more particularly to the Rocky Mountain 

 region and the West ; while the other, " The Dictionary of 

 Elevations," by Dr. J. M. Toner, of Washington, is intended 

 more particularly as a contribution to medical science, hav- 

 ing special reference to the connection between altitude and 

 the occurrence of particular diseases. From this we learn 

 that yellow fever, in particular, is absolutely limited in its or- 

 igin to localities having an altitude of less than five hundred 

 feet, although cases carried above that elevation may prove 

 fatal. 



Hydrography and Navigation. These subjects have re- 

 ceived due attention during the year from the various na- 

 tions of the world, extensive field labors having been prose- 

 cuted, and a large number of charts of harbors, shoals, and 

 other positions, important in navigation having been pub- 

 lished by different hydrographical establishments. 



The United States Coast Survey has conducted operations 

 along the sea-coast of the United States, including a large por- 

 tion of Alaska. Special information regarding explorations 

 in the latter region will be found farther on. It has publish- 

 ed tide tables for both coasts of the United States, and oth- 

 er important works, including numerous charts. The Engi- 

 neer Bureau has continued its survey of the Great Lakes, by 

 methods which constitute a great advance upon those em- 

 ployed in the earlier parts of its work ; and the Secretary of 

 War has suggested the importance of renewing the labor 

 from the beginning, so as to secure uniform and equally sat- 

 isfactory work throughout. The United States Hydrograph- 

 ical Bureau has published many aids to the navigator in the 

 way of charts, notices to mariners, sailing directions in va- 

 rious parts of the world, etc. Among the most important 

 of these works are : No. 40. The West Coast of Africa; Part 

 I. from Cape Spartel to Sierra Leone ; No. 52. The coasts 

 of Spain and of Portugal; No. 56. Remarks on the coasts of 



Lower California and Mexico,by Commander George Dewey ; 



4* 



