22 6 THE POPULAR SCIENCE MONTHLY. 



and adapted to our extensive territory, which have been developed in 

 this country within the last quarter of a century, through the succes- 

 sive mediums of the itineraries of exploring parties, the various boun- 

 dary surveys, Whitney's California Survey, Clarence King's Fortieth- 

 Parallel Survey, Hayden's and Powell's geological surveys, and the 

 geographical surveys and other frontier operations of the Engineer 

 Bureau. The methods in question combine the rapid reconnaissance, 

 the mountain sketch, and the barometrical height upon a precise geo- 

 detic basis, incorporating all reliable information attainable from other 

 sources, especially the land-surveys, which give certain points in roads 

 and streams, and the perimeters of valleys and areas of water. In the 

 end we have a map of which the error is, in general, inappreciable, 

 and the cost in time and money is comparatively insignificant. Yet 

 so faithfully may the features of a country be portrayed in this way, 

 that the map of Lake Tahoe, the subject of this note, is sufficient to 

 guide the engineer in his projects, the geologist in his studies, the 

 tourist on his travels, the soldier on his march, and the emigrant in 

 his search for a home. 



So much for its usefulness, which is the first and principal mission 

 of a map. As a work of art, graphically delineating the configuration 

 of a district of surpassing beauty and variety of scenery, it will, per- 

 haps, possess greater interest to the ordinary observer than any scien- 

 tific value of accuracy and completeness could give it. If a person 

 were called upon to construct an ideal map which should group to- 

 gether specimens of all types of topographical form and the conven- 

 tional signs known to the draughtsman, he could hardly derive from 

 his imagination a chart more comprehensive than this. There is cer- 

 tainly nowhere else in our country an area of equal extent so diversi- 

 fied and broken. Extending from latitude 38 45' to 39 32', and from 

 longitude 119 33' to 120 22', it reaches from the desert inland basin 

 of Nevada to the timbered and grassy mountain-spurs embraced by 

 the multitudinous forks of the American River with which the Sierra 

 Nevada range descends into the Sacramento Valley of California. 



Lake Tahoe is a sheet of water some ten by twenty miles in extent, 

 situated high up in the heart of the Sierras. The mountain-range 

 divides to receive the lake, forming a cup-like space in which its clear 

 waters are gathered. On the map the lake is given the place of honor, 

 in the center. Its surface, being six thousand two hundred feet above 

 sea-level, is not far below the rim of mountains which inclose it, but 

 which, however, slope to great depths in the Carson Valley on the 

 east and toward the Pacific coast on the west. The range in altitude, 

 from the lowest to the highest point on the map, is more than seven 

 thousand feet, there being three mountains Freel's Peak, Pyramid 

 Peak, and Mount Rose standing at three corners of the lake, which 

 are upward of ten thousand feet in height. Thus the subject, taken 

 M a whole, is an admirable one for cartographical expression and 



