24 Mr Harris on Magnetic Intensity, &c. 
either in the rate or arc of vibration, as compared with the oscil- 
lations previously taken, when this artificial aurora was not present. 
38. I have been led to offer these inquiries to the attention 
of the Royal Society of Edinburgh, under an impression that 
they contain enough of useful matter, to render them not un- 
worthy of its consideration : on this account, alone, I venture to 
hope, that the Society may be induced to accept them. The 
measurement of the magnetism of the earth must be at least 
considered a vast and most important object of physical research. 
An attempt, therefore, to perfect the ordinary methods of obser- 
vation, may not be altogether without its use, in the present 
state of general science.* 
PriymoutnH, April 5. 1833. 
* I am much indebted to Mr Cox, maker of Philosophical apparatus at Devon- 
port, for his valuable assistance in the construction of the Instruments described in 
this Paper. 
