DEPARTMENT OF TERRESTRIAL MAGNETISM. I99 



the secular change reverses sign; e. g., from increasing to decreasing west 

 decHnation. This could be done approximately with the aid of the Gauss 

 observations of 1903, the publication of which fortunately came to hand just 

 before we set sail from Colombo. Thus it was found that, in about latitude 

 25^° S. and longitude 60^° E., the average secular change between 1903 

 and 191 1 was such as to increase west declination at the average rate of 

 about 53^' per annum, showing that the line of no change lies somewhat to 

 the eastward of this position. 



The errors in the other magnetic elements, while of less importance to 

 the mariner, are of consequence to theoretical investigations regarding the 

 earth's magnetism. In the magnetic dip, the errors on the present cruise 

 have amounted at times to 4°, and in the horizontal intensity to about one- 

 twentieth part. While some of the results derived from previous analyses 

 of the earth's magnetic field have pointed to the possibility of large and 

 more or less systematic chart errors, it was not suspected that they would 

 reach the magnitude disclosed by the work of the Galilee and of the Carnegie. 



The Carnegie has continued to keep up satisfactorily with the schedule of 

 work laid down for her circumnavigation cruise. At the beginning of the 

 fiscal year she was on her way from the mouth of the Amazon to Rio de 

 Janeiro. After visiting the ports of Rio de Janeiro, Montevideo, Buenos 

 Aires, Cape Town, Colombo, and Mauritius, she again arrived at Colombo, 

 Ceylon, on September 10. The total length of the cruise since leaving 

 Brooklyn, June 20, 1910, up to Colombo, September 10, 1911, or in about 

 134 year's time, is 30,400 nautical miles. This represents something more 

 than one-third of the present cruise, which is to terminate at Brooklyn in 

 June 1913. During this period the magnetic declination has been determined 

 at 318 different points at sea, and the magnetic dip and the horizontal in- 

 tensity at 216 places. In addition, shore observations of all the magnetic 

 elements have been made at seven ports, intercomparisons of magnetic 

 standards have been secured at four places, and various other investigations 

 have been carried out. 



Some further improvements have been made in the instruments and 

 methods used on the Carnegie, as suggested by additional experience gained. 

 Resolutions were passed at the meetings of the magnetic commission of the 

 International Association of Academies, and of that of the International 

 Meteorological Committee held in Berlin last September, showing apprecia- 

 tion of the accuracy achieved in the ocean results and of the magnetic work 

 thus far completed by the Department "towards the accomplishment of the 

 great task of a magnetic survey of the whole earth." 



The Carnegie continues to arouse interest wherever she goes, and every 

 possible courtesy is awarded to her and her scientific personnel at the ports 

 of call. For details of the ocean work, reference must be made to the sub- 

 sequent account. The members of Mr. Peters's party have shown commend- 

 able zeal and enthusiasm in the performance of their respective duties. 



