364« Dr. Page on Galvanic Electricity. 



in the earth, the needle was deflected forty degrees, and the 

 quantity of electricity afforded was sufficient to work the 

 magnets used in Morse's telegraph, as witnessed by the Pro- 

 fessor, and others present. Is the conduction through the 

 material of the building: or through the earth and intervening 

 atmosphere? Probably through the mass of the building, 

 which is constructed of blocks of sandstone, the walls being 

 2| ft. in thickness. A small piece of this stone was found not 

 to conduct this current perceptibly, either dry or when moist- 

 ened with water. But when moistened with acidulated water, 

 the current passed feebly. The fact is interesting whether 

 the air or sandstone becomes the conductor; for if the con- 

 duction be through the building, it is through a material 

 which in a block of eight or ten cubic inches is apparently a 

 non-conductor, but which in the aggregate of the immense 

 pile of the edifice is a conductor. The extreme sensitiveness 

 of the galvanoscope is evident from its frequent disturbances 

 from the slightest causes. I may safely say that the needle is 

 affected by a flash of lightning one hundred miles distant. 

 Whenever a thunder cloud is visible, the needle is deflected 

 at each flash of lightning, and the deflection is in one or the 

 other direction, as the induced current varies according to the 

 direction of the lightning. When the thunder cloud is near, 

 the action upon the needle is very strong and has several times 

 twisted it suddenly off* from the silken fibre to which it is at- 

 tached. When no cloud is visible in the horizon, the needle 

 on certain days — particularly at noon when thunder storms 

 most frequently occur — is subject to frequent disturbances, 

 resembling the former. I may remark here, as evidence of 

 the rapidity of induction, the movement of the needle and flash 

 of lightning appear simultaneous to the eye. 



There are some extraordinary influences upon the needle, 

 having a kind of periodicity, which cannot yet be accounted 

 for, or identified with any meteorological fluctuations. There 

 are also regular changes, which have thus far been noticed 

 during the day. In the morning the current is at its maxi- 

 mum. About 10 o'clock a.m. it declines, and gets to its mini- 

 mum about half-past 2 p.m., when the needle begins to return 

 and arrives within four or five degrees of its maximum of de- 

 flection at 8 p.m. Whether this point observed at 8 a.m. is 

 the real maximum is not known, as I have not been able to 

 observe it in the night. The range of variation from morn- 

 ing to night is about ten degrees. I have not been able to 

 notice any irregularity in these changes except as to the time. 

 The irregular disturbances are very interesting, and may be 

 identical with the magnetic storms of Gauss. Upon certain 



