DEPARTMENT OF TERRESTRIAL MAGNETISM. 353 



the execution in its entirety of the original plan of securing approximately one 

 station for every 10,000 square miles of territory with a uniform distribution 

 over the continent. 



Close upon 600 stations have now been occupied in Australia by the De- 

 partment of Terrestrial Magnetism of the Carnegie Institution of Washington; 

 the data for about one-half of these have ah-eady been pubhshed in the 

 "Researches" of the Department, and the present communication gives the 

 results for those stations occupied since 1914, as extracted from the manu- 

 script for Volume IV of the "Researches," now in press. A great part of the 

 work was done by and under the direction of the author, who describes 

 briefly the various field trips and some of the difficulties encountered. Refer- 

 ence is made to the assistance received in the execution of the work from the 

 government officials in each state. 



The Carnegie Institution magnetic observatory at Watheroo, Western Australia. E. 

 Kidson. (Prepared for the meeting of the Australasia Association for the 

 Advancement of Science at Hobart in January 1921; also presented later 

 before the Royal Society of Tasmania.) 



This paper points out the factors determining the establishment of the 

 Watheroo Magnetic Observator>' of the Department of Terrestrial Magnetism 

 of the Carnegie Institution of Washington. A brief account is given of the 

 essentials for a site to realize the requirements for the observatory.^ 



The reconnaissance work for selection of the site, carried out during August 

 1916 to March 1917 by Mr. W. F. Walhs, with the assistance of Mr. W. C. 

 Parkinson, is described. The speed with which the construction work could 

 be done was hmited by war-time conditions, by the heavy roads, and by the 

 isolated location. A description of the four buildings thus far built is given. 

 The instrumental equipment for absolute and variation work and the observa- 

 tory procedure are briefly described. 



The magnetograph records were begun on December 31, 1918, and have 

 been continuous since. Plans for the erection of an atmospheric-electric 

 observatory and for the installation of continuous recording instruments for 

 both atmospheric-electric and earth-current work are under way. Mr. 

 Wallis, after completing the construction work and initiating the routine 

 observatory program, was succeeded as observer-in-charge in November 1919 

 by the author. 



Records of earthquakes at Watheroo Magnetic Observatory. E. Kidson. Terr. Mag., 



vol. 25, 174 (December 1920). 

 Magnetic disturbances December 4-6, 1920, at Watheroo Observatory. E. Kidson. Terr. 



Mag., vol. 26, 24 (March-June 1921). 

 Earthquake and electric-storm records, December 1920 and January 1921, at the Watheroo 



Magnetic Observatory. E. Kidson. Terr. Mag., vol. 26, 70 (March-June 1921). 



The first of these notes gives detailed circumstances of five earthquakes for 

 which effects were recorded on the magnetograms at the Watheroo Magnetic 

 Observatory during the period November 1919 to September 1920. The third 

 note concerns the earthquake effect extending over 35 minutes of time on 

 December 14, 1920, the record being only in horizontal-intensity trace. Dur- 

 ing severe thunderstorms in the neighborhood of the Observatory on the 

 afternoon of January 16 and 17, 1921, records of the accompanying electrical 

 effects were made on the magnetograms. 



^Cf. J. A. Fleming and W. F. Wallis, "The construction and equipment of the Watheroo 

 Magnetic Observatory in Western Australia," Terr. Mag., vol. 25, 1-6, 1920. 



