No. XXm] APPENDIX. 321 



ttis little iastrument is a very beautiful practical application of pro- 

 found physical laws. 



The cause of all voltaic phenomena is referable to a new attraction, 

 and when this is opposed by obstacles tension is manifested. Tension, to 

 use a figurative expression, is " a desire for action ungratified ;" and thus, 

 as soon as the tension is increased, or the obstacles are diminished, action 

 results, and disintegration, decomposition, or motion occurs. 



It was from the long-continued and close study of the voltaic battery, 

 requisite to enable me to write my treatise on ' Electro-Metallurgy,' that 

 I was led, step by step, to develop the system of physical philosophy 

 lipon which this lecture is based. I could, therefore, tarry and dwell upon 

 this beautiful instrument, did I not remember that on this evening it will 

 be my endeavour to compress into one lecture a slight sketch of the entire 

 l-iinge of physical phenomena. 



Passing from the study of the action of a new attraction upon binary 

 fluid compounds, we may next, with advantage, consider its effect upon 

 solid substances, or substances under the attraction of aggregation, and 

 the electrical machine is well adapted for this purpose. In this case, force 

 is applied to a solid body, whereby tension far exceeding that which is 

 readily obtainable by a voltaic battery is manifested. Whenever the 

 electrical machine is excited by any force, the origin of that force is due 

 to some new attraction, and hence the new attraction is the primary cause 

 of the electrical tension ; and when this is increased sufficiently, or the 

 obstacles decreased, action ensues by a destruction of attractions, such as 

 disintegration, decomposition, or motion, and is frequently accompanied 

 by light, heat, and sound. 



From the above views, the mind is led to suppose that electricity is 

 not' an immaterial essence, imponderable, or spirit attached to matter, to 

 which the effects are due ; but that the phenomena of electricity ai*e 

 entirely owing to the action of a new attraction, upon matter aggregated or 

 composed by former attractions. 



By frictional electricity we can trace how repulsion is a phenomenon 

 of attraction, and not an inherent power of matter ; as by electricity we 

 can readily suspend some of the numerous forces by which any body is 

 held in position, when it moves in the resultant of the others. Two balls 

 suspended close together, when similarly electrified, appear to repel each 

 other ; but in reality they are attracted to surrounding objects. 



Carry the reasoning one step further, we find that which we- term a 

 positive or negative electrical phenomenon is due to the direction in which 

 the new attraction acts, and this direction is analogous to the polaiity of 

 the magnet or the condition of the electrolyte in the voltaic battery. 



Passing from the known to the unknown, we may glance at the 

 thunder-cloud, the awful grandeur of which must for ever appal the 

 human mind. From the dense black masses of clouds which usually 

 accompany this grand natural phenomenon, we have seldom an opportunity 

 of observing that which is taking place ; yet on one occasion, on Forest 

 HiU, I saw that which probably is the cause of the electric action. It was 

 a damp day in June, and there had been much rain previously (the entire 

 sky being covered as it were with misty clouds, through which the sun was 

 seen in an obscured form). Suddenly, without warning or the slightest 

 apparent reason, clouds aggregated above our heads so rapidly, that 



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