APPENDIX B LXXVII 



stations occupied included seven in British Columbia (one for latitude 

 only), two in Alberta, and one in Ontario. The base station in 

 longitude for the points in the west was Field B., C; one station was 

 also connected with Winnipeg, thus forming a triangle to strengthen 

 the longitude of the base station. Observations for personal equation 

 were made before the work began, and also later in the season. For 

 all points except two, 3 inch Cooke transits with registering micro- 

 meters were used, the instruments being adapted for use as zenith 

 telescopes by the addition of latitude levels. For the remaining 

 two points a more portable form of broken-type telescope was 

 employed. 



Geophysics. 



The two Bosch horizontal photographic pendulums and the 

 Spindler and Hoyer, with mechanical registration, have been in opera- 

 tion during the past year. 95 distant earthquakes were recorded 

 during the year, and a local one on Feb. 10 last which was felt over 

 an area of about 200,000 square miles, an area eight times as great 

 as the one in which the local quake of the preceding April was felt. 



The undagraph was installed last September at Chebucto Head, 

 outside of Halifax harbor, and exposed to the broad waters of the 

 Atlantic. It gave good records by the periods of the waves impinging 

 on the shore. Before the sea-end of the pipe was permanently secured 

 it was swept away by a storm, and is now awaiting replacement. 

 In connection with the International investigation of the deformation 

 of the earth by the moon it was originally intended to make the 

 observations at Winnipeg, but from various considerations Ottawa 

 was chosen and two vaults some 23 feet beneath the surface have 

 been built adjoining the Observatory, and one of them is to be devoted 

 to the above purpose, while in the other new seismographs will be 

 installed. 



The magnetic survey of Canada has progressed satisfactorily 

 and 53 stations were occupied during the year, distributed from Quebec 

 to British Columbia. As heretofore the three magnetic elements, — 

 declination, inclination, and intensity have been observed. 



With the present season a systematic gravity survey of Canada 

 by means of three-half seconds pendulums was begun. Observations 

 with the apparatus were made at Washington before and after those 

 at Ottawa, the base-station for Canada; so that thereby our observa- 

 tions will be linked up with those of the United States, and also with 

 the international series. 



