A new Theory of Galvanism. 213 



vanic decomposition is one of complex affinity. The particles of 

 compounds are attracted to the different wires agreeably to their 

 susceptibilities to the positive and negative attraction ; and the 

 caloric, leaving the? electric fluid with which it had been com- 

 bined, unites with them at the moment that their electric state 

 is neutralized. 



As an exciting fluid, I have usually employed a solution of one 

 part sulphuric acid and two parts muriate of soda with seventy of 

 water; but, to my surprise, I have produced nearly a white heat 

 by an alkaline solution barelv sensible to the taste. 



For the display of the heat effects, the addition of manganese, 

 red lead, or the nitrats, is advantageous. 



The rationale is obvious. The oxygen of these substances 

 prevents the liberation of the gaseous hydrogen, which would 

 carry off the caloric. Adding to diluted muriatic acid, while 

 acting on zinc, enough red lead to prevent effervescence, the 

 temperature rose from 70 to 110 Fahrenheit. 



The power of the Calorimotor is much increased by having the 

 communication between the different sheets formed by very large 

 strips or masses of metal. Observing this, I rendered the sheets 

 of copper shorter by half an inch, for a distance of four inches of 

 their edges, where the communication was to be made between 

 the zinc sheets; and, vice versa, the zinc was made in the same 

 •way shorter than the copper sheets where these were to com- 

 municate with each other. The edges of the shortened sheets 

 being defended by strips of wood, tin was cast on the interme- 

 diate protruding edges of the longer ones, so as to embrace a 

 portion of each equal to about one quarter of an inch by four 

 inches. On one sid-; the tin was made to run completely across, 

 connecting at the same time ten copper and ten zinc sheets. On 

 the other side, there was an interstice of above a quarter of au 

 inch left between the stratum of tin embracing the copper, and 

 that embracing tiie zinc plates. On each of the approaching 

 terminations of ti)e connecting tin strata was soldered a kind ot 

 forceps, formed of a bent piece of sheet brass furnished with a 

 screw for pressing the jaws together. The distance between the 

 different forccjis was about two inches. The advantage of a 

 very close contact was made very evident by the action ot the 

 screws; the relaxation or increase of pressure on the connecting 

 wire by turning them being productive of a correspondent change 

 in the intensity of ignition. 



It now remains to state, tliat by means of iron ignited in this 

 apparatus, a fixed alkali may be decomposed extemporaneously. 

 If a connecting iron wire, wiiile in combustion, be touched by the 

 hydrate of potash, the evolution of potassium is demonstrated by 

 a rose-coloured flame. The alkali mav be ai)plied to the wire iti 



3 ' small 



