Chemical Science. 613 



contact of dissimilar metals having no effect. This has been vigo- 

 rously controverted by MM. Pfaff, Marianini, &c. : but we wish here 

 merely to quote the experiment of M. Matteuci, who has joined in 

 the investigation. 



He was convinced by Pfaff 's experiments, that electricity could be 

 developed by contact only ; but to be more convinced, he made cer- 

 tain experiments on frogs. First, he assured himself that there was 

 no chemical action between distilled water perfectly free from air, 

 and zinc, either alone or in contact with copper. After contact of 

 many hours, the most sensible tests could not shew the presence of 

 the oxide of zinc or copper. It would, therefore, be very unjust (in 

 the present question) to assume that there is chemical action because 

 there is development of electricity. Being sure upon this point, a pre- 

 pared frog was then suspended from a rod of zinc, which was fixed 

 at the bottom of a gas jar, and connected with a long copper wire, so 

 that nothing more was required to produce the well known contrac- 

 tion than to touch the muscles of the legs with the copper wire. 



To remove every suspicion of chemical action, the frog was washed 

 in distilled water, freed from air, so as to remove all animal fluid. It 

 was then suspended by the nerves from the zinc, the jar filled with 

 distilled water, and then with pure hydrogen : but on touching the 

 limbs with the copper wire, the same contractions took place as in 

 common air. The experiment was repeated in vacuo, carbonic 

 oxide, carbonic acid, and oxygen, sometimes dry and sometimes 

 damp, but always with the same result. 



M. Matteuci, therefore, remains convinced that the mere contact 

 of different metals is able to develope electricity ; although he admits 

 with most philosophers, that chemical action exerts an influence over 

 this force just as heat does in thermo-electric experiments.* 



2. CONDUCTING POWERS OF LIQUIFIED GASES. 

 (K. T. Kemp.) 



By making liquified sulphurous acid gas a part of the circuit in a gal- 

 vanic battery of 250 pairs of plates, shocks were received, water was 

 decomposed, and the galvanometer was acted on as if a continuous 

 metallic communication had existed. Liquid sulphurous acid is there- 

 fore an excellent conductor of electricity. Cyanogen, on the contrary, 

 was found to be a perfect non-conductor, even to a voltaic current 

 from 300 pairs of plates. Liquified chlorine was also found to be a 

 perfect non-conductor of electricity from a battery of 250 pairs of 

 plates. The author then tried liquified ammoniacal gas, but could 

 not ascertain whether it was a conductor or non-conductor of elec- 

 tricity. It is, in all probability, a non-conductor f. 



3. GENERATION OF STEAM BY HEATED METAL. 

 In boilers of high pressure engines, the heat applied to a part not 

 * Ann. de Chimie, xlv. 106. f Edin. Journal of Nat, and Geog. Science. 



VOL. I. May, 1831. 2 S 



