370 



SCIENCE. 



[N. S. Vol. XI. No. 271. 



Bcience, but for tLe general information of 

 others working on other lines. To this end 

 a bird's-eye view of the present state of the 

 particular science, together with a state- 

 ment of the more important and interesting 

 recent developments, will serve better than 

 a detailed catalogue of the separate steps 

 which malve up recent progress. 



By studying the recent reports of the In- 

 ternational Geodetic Association and the 

 geodetic reports from various countries, one 

 is gradually convinced that there is well- 

 sustained activity in geodetic operations in 

 many countries, that geodetic facts are be- 

 ing steadily accumulated, and that steady 

 progress is being made in improving meth- 

 ods and instruments. Having realized this, 

 one naturally looks for published collec- 

 tions of results, and for some reasonably 

 complete and well-digested scientific papers 

 showing the relation between existing theo- 

 ries and results. One expects to find a 

 considerable portion of the accumulated 

 facts published in convenient form for the 

 use of the hydrographer, topographer, tlie 

 physicist, and the engineer. But this ex- 

 pectation is not realized. Of the great 

 store of accumulated facts only a small part 

 are as yet published in any complete or 

 systematic way. The remaining ones are 

 published, if at all, in such a fragmentary 

 and disconnected form as to lose much of 

 the value which thej"- would otherwise have. 

 Again, one looks in vain for any compre- 

 hensive study in recent years of the earth's 

 figure and size. Since the publication by 

 Colonel Clarke, some twenty years ago, of 

 his values for the polar and equatorial radii, 

 no corresponding comprehensive investiga- 

 tion has appeared in print. 



It is not easy to understand why publica- 

 tion and discussion should lag so far behind 

 the measures in the field. One considera- 

 tion presents itself, however, as a partial, 

 though insufficient, explanation. To ad- 

 just a network of triangulation requires an 



amount of expert computing which, as to 

 time and cost, seems disproportionate to the 

 field-work. Consequently, there is a de- 

 cided tendency for the computations to be 

 several years behind the corresponding field 

 operations. By the time computations are 

 finished for a given area new results of ob- 

 servations are available in that area or in 

 adjacent connecting areas. Thus it always 

 seems that the time for publication has not 

 come, since whatever might be published 

 would of necessity be incomplete. 



It may be admitted that in many cases 

 the computations made have been more 

 complex and laborious than was warranted 

 by the observations. The problem is one 

 which lends itself to many theoretic refine- 

 ments leading to long computations. 



In what is above written as to delays in 

 publication and computations needlessly 

 prolix the writer must not be understood as 

 referring chiefly to work in United States. 

 Publication is apparently no further behind 

 in this country than in other countries, 

 with the possible exception of Great Britain. 

 In simplifying the computations in office to 

 correspond with the accuracy attained in 

 the field, this country is easily foremost. 



The years 1898 and 1899 mark an epoch 

 in the history of geodesy in the United 

 States. In 1898 the last of the field opera- 

 tions on the great transcontinental arc, ex- 

 tending from the Atlantic to the Pacific 

 along the thirty-ninth parallel, were com- 

 pleted. During the same year the field 

 measures of the oblique arc parallel to the 

 Atlantic coast were also completed. In 

 1899 the necessary observations to complete 

 an oblique arc in California, extending from 

 Point Arena to the Mexican boundary, 

 were brought to a close. In 1899 also, but 

 little more than a year after the completion 

 of the last field measurements, the compu- 

 tations connected with the arc of the thirty- 

 ninth parallel were completed and the re- 

 sults put in form for the printer. 



