112 EEPOKT — 1892. 



sun-heat. Closing the shutters and blinds of the one window in the 

 room does not alter the angular displacements. The N. and S. pointer 

 of a glass fibre instrument standing on the S.E. corner of the column may- 

 be altered by lighting a small stove which stands within 3 feet of the 

 column, and raising the temperature of the room 20° to 30° Fahr. In a 

 few hours this corner of the column becomes quite warm to the hand, 

 and the pointer shows that the southern side has been warped or tilted 

 upwards. Although the fire may burn all day, I do not observe any 

 change in the other instruments, and it is therefore difficult to imagine 

 that the deflections which have been noted are the immediate result of a 

 chano-e in the temperature or hygrometric state of the atmosphere in the 

 room where the column is situated. The character of the movements 

 is hardly such as might be expected from changes in declination. At 

 the Magnetical Observatory, about two miles distant from my house, 

 whatever changes have been recorded do not coincide either in character 

 or in time with the movements under discussion. 



The conclusion arrived at is, that from time to time there is evidence 

 that the column in my house is tilted sometimes quickly, but more gene- 

 rally slowly. The cause of this tilting is not inside the house, but outside. 

 It may be local, and due to variation in the temperature or the moisture 

 in the ground. 



To determine whether the tilting extends over a considerable area a 

 second photographic recorder is being erected in a seismological labora- 

 tory about 400 yards distant from my private observatory. 



6. On January 28, at about 11.20 p.m., a small earthquake took place, 

 after which it was observed that the N. S. pointers of all the instruments 

 had been displaced in the same direction. It appeared as if the south 

 side of the column had been slightly tilted. East and west pointers 

 were not disturbed. Subsequent earthquakes in February did not pro- 

 duce any change. 



Earthquakes are recorded as streaks of light across the plate, and as 

 the instruments are so sensitive, they are capable of recording disturb- 

 ances which ordinary instruments fail to indicate. 



In making these investigations I am now receiving valuable assistance 

 from Mr. F. Townley, in Yokohama, and Mr. James Murdoch, in Omori, 

 each of whom is provided with tromometers. My colleague. Professor 

 W. K. Burton, has given me most valuable assistance in carrying out the 

 photographic part of my work. 



Earth Tremoes and Firedamp. 



In 1884 I repoi'ted to this Association that in the previous year I had 

 established a tromometer and other instruments underground in the 

 Takashima Colliery, near Nagasaki. Shortlj' after they were put up a 

 fall of the roof cut off access to the chamber where they were placed, and 

 ever since they have remained buried beneath the bed of the Pacific 

 Ocean. As Mr. John Stoddart, who took charge of the instrument, has 

 died, and Nagasaki is so far distant, I have not been able to re-establish 

 these observations, one of which was to determine whether the giving off 

 of firedamp was in any way connected with earth tremors. 



In the ' Proceedings of the Nox'thern Institute of Mechanical and 

 Mining Engineers,' Mr. Walton Brown drav^s attention to the possible 



