LXXXVIII ROYAL SOCIETY OF CANADA 



States; consideration being also given to continental and oceanic areas, 

 as well as the position of the Great St. Lawrence and Champlain Fault. 

 Other geological features have not yet been considered. These micro- 

 seisms manifest themselves in all parts of the world, but their detection 

 depends in a measure upon the sensitiveness of the seismograph. Their 

 full interpretation still awaits solution. The most prominent phenom- 

 enon synchronous with the occurrence of microseisms here, is the pre- 

 sence of an area of low barometer surrounded by steep gradients over 

 the Gulf of St. Lawrence. 



Investigation ha? I)een carried on as to the tilting of the pier on 

 which the seismograph is mounted, produced by varying barometric 

 pressure passing over the elastic crust of the earth. The sensitiveness 

 of the instrument pei-mits of reading an inclination, of one-fiftieth of a 

 second of arc, which is equivalent to a grade of one foot in two thousand 

 miles. For the further study of microseisms there are being installed 

 a micro-barograph and statosoope, also a Callendar electric recorder, for 

 obtaining a continuous record of the temperature of the air. 



Terrestrial Magnetism. — During the past season systematic magne- 

 tic observations have been made for the determination of the three ele- 

 ments—declination, inclination and intensity. The type of instrument 

 was the Tesdorpf: declination being determined by a. fibre (phosphor- 

 bronze) declinometer; inclination by a dip-circle; and intensity by oscil- 

 lations and deflections. The following stations, beginning in the east 

 and arranged in order of longitude, were occupied: Sydney, Mulgrave, 

 Antigonish, Pictou, Truro, Pugwash, Shediac, Moncton, Eichibucto, 

 Newcastle, Bathurst, St. John, Mispec, Matapedia, Meg'antic, Tring 

 Junction, Sherbrooke, Farnham, Brockville, Ottawa, Kingston (2 Sta- 

 tions), Kingston Junction, Sharbot Lake, Pembroke, Barry's Bay, 

 Mattawa, Joe Lake, North Bay, Rose Point, Sudbury and Chapleau. 

 The difference of longitude between the first and last station is 23° 15', 

 and the difference in declination, 21° 40'. Chapleau is but a short dis- 

 tance east of the agonic line. Speaking generally, the change of de- 

 clination from place to place follows fairly the change in longitude, with 

 the notable exception at Kingston, where local attraction influences the 

 direction of the magnet very much, twenty degrees and more, for de- 

 clination. 



Besides the practical value and importance of such observations, 

 particularly for the older settlements, where nearly all the original sur- 

 veys were made with chain and compass, and the re-establishing of old 

 lines is dependent upon a knowledge of the change that the direction of 

 the magnetic meridian has undergone, they will supplement the mag- 



