National Geographic : 1896 Apr
150 RECENT TRIANGULATION IN THE CASCADES with which the Coast Survey has mapped out the waters of the United States. Historically the investigations set on foot by the Smithsonian Institution should be noticed, for from these has come, directly or indirectly, nearly all our information concerning hydrography in its broader aspect. The systematic study of precipitation was first begun under this institution, and after being well established was turned over to the Signal Office, the predecessor of the Weather Bureau. In other lines the Smithsonian Institution has in similar manner shown the way, and when feasible has entrusted the continuation of the investigations to other organ izations, in order that it might concentrate its own energies on other original lines of research tending to " the increase and dif fusion of knowledge." RECENT TRIANGULATION IN THE CASCADES By S. S. GANNETT, United States Geological Survey During the field season of 1895, the United States Geological Survey extended triangulation over a portion of central Wash ington. An astronomical determination of Ellensburg having been made, a base was measured on the roadbed of the Northern Pacific railroad. From this base, triangulation was extended into the Cascade mountains. Horizontal angles were measured with an eight-inch theodolite, reading by micrometers to two seconds of arc. Vertical measures were also taken upon some of the more prominent peaks, angles being measured by a vertical circle four and one-half inches in diameter and reading by ver nier to one minute of arc. Elevations are based upon the height of the Northern Pacific railroad at Ellensburg. The preliminary computation gives the elevation of mount Aix, by reciprocal observations to and from stations in the base expansion, 28 miles distant, as 7,815 feet above sea level. Mount Rainier, by foresights from mount Aix, 24 miles dis tant, is found to be 14,532 feet, mount Adams, likewise by fore sights from mount Aix, 42 miles distant, 12,470 feet, and mount Stuart, by foresights from several stations in the base expansion 24 to 30 miles distant, 9,500 feet, above sea level.