The Ketchikan miner., 1915-02-25
HANDBOOK OF THE COAST
 AND GEoDETIC SURVEY


 issued especially for distribution at the Panama Pacific International FIX position pamphlet entitled "Cnitej States Coast and Geodetic Survey, Description of its Work, Methods and Organization.
 While this work is intended for the general reader it also gives T concise account of the more important scicn- tific features of the work of rho Sur vey and of the Improvements that have been made in recent years in instruments and methods. In the sec tion relating to hydrography there is a description of the wire drag, an apparatus so valuable in discovering fhidden dangers that escape detection by the ordinary method of sounding. P In the section relating to tides is a brief description of the improved tide.predicting machine which with one operator predicts the tides for one year in advance for any port. and does the work of 100 men. To set the machine for any station ani tabu Hate the tides for year for any port takes not more than 12 hours. In the article on the base lines there is description of the modern method of measurement with tapes of invar metal now used in the Sur vey to the exclusion of any other method. The invar metal Is m al lfloy of nickel and steel, the a'lvan- tage of which for this and many ether purposes is that it's rate of expansion and contraction under changes Of temperature is about 1-25 that of steel. so that the important source of error due to temperature changes is practically eliminated. Tho use of tapes has decreased the cost of base measurement by about B per cent and greatly increased the rapidity of the work.
 Under the head of astronomy is z  description of the Taleott method ot observing latitude by means of which results of superior accuracy are at tained. This method has long been used by the Survey in precise determ- nations. The instruments used in the determination of longitude by the telegraphic method are also de- scribed.
 The use of motor truck for the transportation of parties engaged in latitude work is mentioned as having increased the rapidity and decreased the cost of such work by large per cent.
 There are numerous illustrations of instruments and apparatus. parties at work in the field. etc, and maps showing the extent and character of the work.
 When the survey was begun under Ferdinand R. Hassler. the entire coast of the United States was on the Atlantic and Gulf of Mexico. The | acquisition of California. Oregon and Washington. and later Alaska. Porto Rico, Hawaii and the Philippine Isl ands, greatly extended the scope of the survey and brought new prob | lens to be solved The extension of the triangulation into the interior so as to form a geodetic connection be tween the Atlantic and Pacific coasts; the extension of this system so as to furnish accurately located geographic positions and elevations in all parts of the United States; and the hcg,n- ming of systematic magnetic survey of the whole country are among the important works that have beer under taken since the original plan of Has sler was adopted.
 The results of the operations of this bureau are of importance to the navigator. the surveyor, the engineer. and to all who are interested in works of public improvement requiring ac- curate surveys as their basis. The publication may be obtained without charge from the Division of Publications, Department of Conner ce, Washington, D. c.
 -f- The Daily Miner Al nar nnnfh