abstracts: geodesy 75 



recognition when a famous geodesist, F. R. Helmert, arose and congratu- 

 lated the Americans on having introduced a new epoch in geodesy. 



Surveys were made of various uncharted localities in Alaska and 

 excellent progress was made in surveying the waters of the Philippine 

 Archipelago, more than 10 per cent of the estimated general coast line 

 being covered during the year. 



Important improvements were made in the construction and use of the 

 long wire drag and its length was increased to 8,400 feet in open water. 



The report announces that the policy of orienting charts with the meri- 

 dian adopted twenty years ago will be continued and a definite pro- 

 gramme followed of eliminating the old-style charts and replacing them 

 with a smaller number on the mercator projection. The report is 

 supplemented by six appendixes. Details of field and office operations 

 are given in Appendixes 1 and 2. Appendixes 3-6 are abstracted sepa- 

 rately. Isaac Winston. 



GEODESY. — Primary base lines at Stanton, Texas and Deming, New 

 Mexico. William Bowie. App. No. 4, Rept. Coast and Geodetic 

 Survey for 1910. Pp. 143-171, 5 figs. 1911. 



Nickel-steel or invar tapes were adopted by the Coast and Geodetic 

 Survey for the measurement of primary bases in 1906. (See Appendix 

 4, Report for 1907.) The first primary bases measured in the United 

 States with invar tapes alone are those at Stanton, Tex., and Deming, 

 N. M., in the Texas-California arc of primary triangulation in 1909 and 

 1910 respectively. 



The two bases in question have lengths of 13.2 and 15.5 kilometers. 

 The cost of measuring on the field was $56 per kilometer on the Stanton 

 Base and $39 per kilometer on the Deming Base. Work on the Stanton 

 Base required 17 days, and on the Deming Base 13 days. Measure- 

 ments with the tape (50-meter) were made on 6 days at Stanton and 3 

 days at Deming, nearly all in daylight. The probable errors of the 

 resulting lengths are 1/2,561,00 for the Stanton Base and 1/1,961,000 

 for the Deming Base. These are comparable with those obtained 

 with the best base bars. 



A new and very much lighter form of tape stretcher was used on 

 these bases. On the Deming Base five supports were used for each 

 tape length. With this number wind caused little or no trouble. No 

 standardizations were made in the field. Those made at the Bureau 

 of Standards before and after the measurement of each base showed 

 that no one tape changed in length as much as 1/400,000. W. B. 



