VOL XLVI.] PHILOSOPHICAL TRANSACTIONS. 123 



call the animal spirits; and is the author of life and motion. But we know not 

 the immediate mode of muscular motion, any more than how, in inanimate 

 matter, it causes the vibrations of an earthquake. 



13. The great question then with us is, how the surface of the earth is put 

 into that vibratory and electric state by heat and dryness ? We must needs acquit 

 the internal of the earth from the charge of these superficial concussions. How 

 is the ethereal fire crouded together, or excited, so as to cause them ; seeing, in 

 our ordinary electrical experiments, we make use of friction } 



But that friction alone does not excite electricity, we know, from the obvious 

 experiment of flint and steel ; where the suddenness of the stroke, and hardness 

 of the matter does it. Another method of exciting it, is the letting ofFa number 

 of great guns ; which so crouds the ethereal fire together, as to electrify glaSs 

 windows ; observed by Dr. Stephen Hales. The aurora borealis, australis, all 

 kind of coruscation, meteors, lightning, thunder, fireballs, are the effects, and 

 may reciprocally be the cause, of electricity ; but how, in particular, we 

 know not. 



Come we to the animal world, we must needs assert, that all motion, volun 

 tary and involuntary, generation, even life itself, all the operations of the vege- 

 table kingdom, and an infinity more of nature's works, are owing to the activity 

 of this electric fire ; the very soul of the material world. And, in my opinion, 

 it is this alone that solves the famous question, so much agitated with the writers 

 in medicine, about the heat of the blood. Hrfw these, how earthquakes, art 

 begun and propagated, we are yet to seek. 



We may readily enough presume, that the contact between the electric and 

 the non-electric, which gives the snap, and the shock, must come from without, 

 from the atmosphere; perhaps by some meteor, that crouds the ethereal fire 

 together, causes an accension in the air, in the point of contact, on the earth's 

 surface ; perhaps another time by a shower of rain. We may as readily con- 

 clude, that, though the original stroke comes from the atmosphere, yet the at- 

 mosphere has no further concern in it : no aerial power, or change therein, can 

 propagate itself so instantaneously over so vast a surface as 4000 miles square : 

 Therefore the impetuous rushing noise in the air, accompanying the shock, is 

 the effect, not the cause. But surely there is not a heart of flesh that is not 

 affected with so stupendous a concussion. Let a man estimate his own power 

 with that which causes an earthquake, and he will be persuaded that somewhat 

 more than ordinary is intended by so rare and wonderful a motion. 



That great genius Hippocrates makes the whole of the animal economy to be 

 administered by what we call nature , and nature alone, says he, suffices for all 

 things to animals: she knows herself, and what is necessary for them. Can we 

 deny then that he here means a conscious and intelligent nature, that presides 



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