170 



ON THE IDENTITY OF LIGHT, HEAT, 



formalion of a complete circuit; and yet there was no circuit 

 formed in most of these experiments, nor did the completion 

 of the circuit at all augment, decrease, or influence any of the 

 results. (See Experiments, Dec. 15.) 



That the effects are due to the influence of the solar rays 

 upon the southern extremity of the helix, was manifested on 

 several occasions by the same and frequently an increased 

 action upon the needle ensuing by the shading of the other 

 parts of the helix. (See Experiments, Jan. ^2nd and 27th.) 



The unexpected change which took place in the direction 

 of the needle on the 22nd of January, at 12 noon, and which 

 appears to have continued from that period to the present at 

 all times after a given hour, — being to the right hand with the 

 early and winter sun, and to the left hand when the latter has 

 advanced far above the horizon, — evinces that the influence of 

 the rays in inducing the direction of the current in the helix 

 at these two pei'iods is ajitagonistic ; this is also displayed by 

 the stationary or vibrating condition of the needle at the 

 interval between these two periods. This vibratory motion is 

 also observed at all times when two antagonistic currents are 

 induced. (See Experiments, Jan. 12th, 23rd, and 27th.) 



The vertical action of the rays upon the helix in the 

 production of current, and its electro-magnetic effects upon 

 the needle, appear to depend upon the intensity and 

 momentum of the solar rays, which probably enter into and 

 traverse the wires in that direction which most nearly cor- 

 responds to the direction of the rays ; the deflection of the 

 needle in each instance corresponding, according to known 

 laws, to the direction of the current thus induced. 



That the action is augmented in proportion to the number 

 of coils of the helix acted upon, was evidenced in several 

 experiments, and particularly in those of the 22nd of January. 



Thus it appears that each ray as it falls upon a coil of the 

 helix traverses it with a given degree of momentum, and that 

 when the current thus produced arrives at the continuous 



