ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

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 this issue. 



GEODESY. — Triangulation in West Virginia, Ohio, Kentucky, Indiana, 

 Illinois and Missouri. A. L. Baldwin. U. S. Coast and Geo- 

 detic Survey Special Publication No. 30. Pp. 67. 1915. 



This publication contains the positions of 369 triangulation sta- 

 tions which lie within the limits of the six states mentioned in the 

 title, and most of which form that part of the Transcontinental Tri- 

 angulation extending from the Atlantic to the Pacific. The publi- 

 cation supplements the information given in Special Publication No. 4 

 which appeared in 1900 and contained features of special interest to 

 scientists. Positions are there given of only the principal stations and 

 only a few of them are described. Since the appearance of Special 

 Publication No. 4 the United States Standard Datum, called the North 

 American Datum since its use by Mexico and Canada, was adopted 

 and it became necessary to place the old positions on that datum. 

 In Special Publication No. 30 there are given the geographic positions, 

 on the North American Datum, of all stations in the area covered, to- 

 gether with all available descriptions of these points. 



In addition to the above-mentioned data, this publication gives the 

 results of a trigonometric connection made in 1914 between the de- 

 tached pieces of triangulation to the north and south of Louisville, 

 Kentucky. It includes also the results of a primary base line measured 

 in 1879 with six-meter contact-slide bars. Such apparatus is no longer 

 used in the field in the United States, as the long invar tapes or ribbons 

 have recently superseded all forms of bars in base line measurements. 

 The field work covered by this publication was done between 1871 and 

 1914, but all details are omitted, except for the primary triangulation 

 done in Indiana in 1914. 



Aside from its scientific interest, the volume has a large practical 



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