24 CARNEGIE INSTITUTION OE WASHINGTON. 



to "The Composition of the Atmosphere with Special Reference to its 

 Oxygen Content," and proves the remarkable fact of the essential constancy 

 of this element in the atmosphere. 



Highly effective progress has been made by this department during the 

 past year in its magnetic survey of the globe. By means of the non-mag- 

 De artmentof "^^^^ ^^^'P Carnegie it is now easier to make a magnetic 

 Terrestrial survcy of the occau arcas than of the land areas, for the 



Magnetism. former are now more readily accessible than the latter. 

 At the end of the preceding fiscal year the Carnegie was at Batavia, Java. 

 On November 21, 1911, she set sail for an additional circuit of the Indian 

 Ocean, whence she proceeded to Manila, Philippine Islands, where she 

 arrived February 3, 191 2. From Manila she proceeded to Suva, thence to 

 Tahiti, and is now en route to Coronel, Chili. During the fiscal year she 

 traversed about 28,000 miles. Her courses are arranged to intersect as 

 frequently as possible her own previous tracks, those of the Galilee, and 

 those of previous expeditions on which magnetic elements were observed. 

 Valuable checks on the determinations of these elements are thus secured, 

 and in case of considerable intervals between the dates of different deter- 

 minations, data for secular variation of the magnetic elements are also ob- 

 tained. As related in the report of a year ago, unexpectedly large errors 

 were found in the best magnetic charts of the Indian Ocean and for some 

 parts of the Pacific Ocean. In order that corrections may be speedily ap- 

 plied to such charts the results of the cruises of the Carnegie are promptly 

 made known to the principal hydrographic offices of the world. It is ex- 

 pected that the Carnegie will complete her present circumnavigation of the 

 world near the end of the next fiscal year. 



Observations have been continued simultaneously on land areas, embrac- 

 ing portions of five continents and about twenty different countries. Many 

 noteworthy series of transcontinental stations have now been completed. 

 Of these, one extending across the entire continent of South America, begin- 

 ning at Para, at the mouth of the Amazon, and extending to Callao on the 

 Pacific coast, by wa}' of the Amazon and Ucayali rivers and Lima, has been 

 finished during the past year. 



The first volume of researches of the department, giving the results of 

 land observations from the time of its establishment in 1905 down to the 

 end of the year 1910, is now in press. The final computations of the ocean 

 observations made during the various cruises of the Galilee and the Carnegie 

 are also well advanced for a second volume. Many improvements in in- 

 strumental appliances have been made during the year in response to needs 

 and suggestions arising from the extensive experience of the department on 

 land and sea. One of the most important of the new appliances devised is 

 that called an "earth inductor," which permits the measurement of the dip 

 of the magnetic needle with increased precision and decreased labor over 



