6 PRACTICAL RESULTS OF THE PROGRESS 



of intelligence, waggons are moved by it, constructions made, 

 vessels caused to perform voyages in opposition to wind and 

 tide, and a power placed in human hands which seems almost 

 unlimited. To these novel and still extending improvements 

 may be added others, which, though of a secondary kind, yet 

 materially affect the comforts of life ; the collecting from fos- 

 sil materials the elements of combustion, and applying them 

 so as to illuminate, by a single operation, houses, streets, and 

 even cities. If you look to the results of chemical arts, you 

 will find new substances of the most extraordinary nature ap- 

 plied to novel purposes ; you will find a few experiments in 

 electricity leading to the marvellous result of disarming the 

 thunder-cloud of its terrors, and you will see new instruments 

 created by human ingenuity, possessing the same powers as 

 the electrical organs of living animals *. To whatever part of 



* Sir Humphry Davy here alludes either to the Electrical Battery, the 

 instrument for accumulating common electricity ; or to theVoltaic Pile, the 

 instrument, of more recent discovery, by which we accumulate that kind of 

 electricity which is most commonlyknown under the appellation of Galvanism. 

 The action of the former, when weakly charged, was compared by Mr. Ca- 

 vendish, to that of the electrical organs of the Torpedo (or Crampfish,) and 

 Gymnotus (or Electrical Eel) : while Volta, when he invented, or rather dis- 

 covered, the instrument, having very different properties and powers, which 

 bears his name, but which is more commonly, though with less propriety, 

 termed the Galvanic Battery, imagined that he had made a perfect resem- 

 blance of the electrical organs of those fishes. 



From Sir Humphry's "Account of some Experiments on the Torpedo" (his 

 last production of an exclusively scientific nature) we should infer that Mr. 

 Cavendish's conjecture, with respect to that animal at'least, was nearest to 

 the truth. Sir Humphry found, that the electricity of the Torpedo, like that 

 of the weakly charged battery, did not in the slightest degree affect the 

 needle in the magnetic electrometer, while the smallest and weakest voltaic 

 combinations, " but in which some chemical action was going on," produced 

 an immediate and permanent deviation of the needle. These experiments, Sir 

 Humphry observes, though he draws the inference with great caution, " seem 

 to show a stronger analogy between common and animal electricity, than be- 

 tween voltaic and animal electricity : it is however," he continues, " I think- 

 more probable that animal electricity will be found of a distinctive and pe- 

 culiar kind." 



It must at the same time be remarked, that the form of the Voltaic pile, 

 which latterly appeared to its inventor to fulfill the conditions of the electri- 

 cal organs of the Torpedo, and which, as mentioned in the paper just quoted, 

 he exhibited to Sir Humphry Davy, at Milan, in the summer of 18 i 5, has 

 not yet been shown to affect the magnetic electrometer ; and from its not 

 decomposing water, as well as from the nature of the imperfect conductor 

 in it, which was honey, or a strong saccharine extract, there is room to 

 suppose, that (like some of the piles constructed by M. Zamboni ?) it may 

 be devoid of sensible chemical action, and therefore that it will not 

 affect the magnetic needle. Should this prove to be the fact, we must pro- 

 bably consider the electricity of the Torpedo to be Voltaic : that is, to be of 

 the same kind as that developed by the Galvanic Battery. 



As these pages are intended for the perusal of those persons who may 



