VOL. LXIII.] PHILOSOPHICAL TRANSACTIONS. 477 



charged, contain a dense electricity capable of forcing a passage through an inch 

 of air, and afford the phenomena of light, sound, attraction, and repulsion. 

 But if the quantity condensed in this phial, be made rare by communicating it 

 to 2 large connected jars, whose coated surfaces shall form together an area 400 

 times larger than that of the phial (I instance these jars because they are such 

 as I use); it will, thus dilated, yield all the negative phenomena, if I may so 

 call them, of the torpedo; it will not now pass the 100th part of that inch of 

 air, which in its condensed state it sprung through with ease; it will now refuse 

 the minute intersection in the strip of tin foil ; the spark and its attendant sound, 

 even the attraction or repulsion of light bodies, will now be wanting; nor will a 

 point, brought however near, if not in contact, be able to draw off the charge : 

 and yet, with this diminished elasticity, the electric matter will, to effect its 

 equilibrium, instantly run through a considerable circuit of different conductors 

 perfectly continuous, and make us sensible of an impulse in its passage. 



Let me here remark, that the sagacity of Mr. Cavendish in devising, and his 

 address in executing, electrical experiments, led him the first to experience with 

 artificial electricity, that a shock could be received from a charge which was 

 unable to force a passage through the least space of air. But, after the 

 discovery, that a large area of rare electricity would imitate the effect of the 

 torpedo, it may be inquired, where is this large area to be found in the animal ? 

 We here approach to that veil of nature, which man cannot remove. This 

 however we know, that from infinite division of parts infinite surface may arise, 

 and even our gross optics tell us, that those singular organs, so often mentioned, 

 consist, like our electric batteries, of many vessels, call them cylinders or 

 hexagonal prisms, whose superficies taken together furnish a considerable area. 



I rejoice in addressing these communications to you. He, who predicted and 

 showed that electricity wings the formidable bolt of the atmosphere, will hear 

 with attention, that in the deep it speeds a humbler bolt, silent, and invisible: 

 He, who analyzed the electrified phial, will hear with pleasure that its laws 

 prevail in animate phials: He, who by reason became an electrician, will hear with 

 reverence of an instinctive electrician, gifted in his birth with a wonderful 

 apparatus, and with the skill to use it. 



Explanation of the Plate of the Male and Female Torpedo, or Electric Ray. 



-PI. 9, fig. ], is a view of the under surface of tlie female. — a. An exposure, on flayirg off the skin, 

 of the right electric organ, which consists of white pliant columns, in a close, and for tlie most part 

 hexagonal arrangement, giving the general appearance of a honey comb in miniatuie. These 

 columns have been sometimes denominated cylinders; but, having no interstices, tliey are all 

 angular, and chiefly 6 cornered. — b. The skin which covered the organ, showing on its inner side, a 

 hexagonal net work.^. The nostrils in tlie form of a crescent. — d. The mouth in a crescent 

 contrary to that of the nostrils, furnished with several rows of very small hooked teetli. — e. The 

 branchial apertures, 5 on each side.— f. The place of the heart.— g, g, g. The place of the 2 



