160 ELECTRO-CHEMICAL PRINCIPLES. 



and oxigen, bodies, but from the last it cannot be disengaged by the affinity 



which arc both f any electropositive body to the lead 5 but for that purpose 



sulph. 3cid and l he affinity of another body, more electronegative than itself, 



the sulphur namely oxigen will be required. Sulphur has, therefoie, occasion 

 nay he disen- e ., ...\ , r „ . ■ <• 



gaged by many * or °PP°site electricities, in order to effect its separation from 



d. positive these two different combinations. It is well deserving of atten- 

 in sulphm-etof ^ on ' ^' at WDeD such an electronegative combustible is cora- 

 Jeadnoel. pos. bined with an electropositive oxide, the combustibility of the 

 the lead 'bu* *° rmer ( or * lts electropositive relation as to oxigen) is consider- 

 an e. neg. ably increased ; probably because its electronegative dispositions 



bodv,viz. have been destroyed by the positive electricity of the oxide. 



oxigen is re- J J r J 



quired. We observe this in the great oxidability of sulphur and of 



Cause why phosphorus, combined with the alkalis, or alkaline earths. In 



sulphur and r r 



phos. are ren- a combination of two combustible bodies of opposite electro* 



«ierc! mere chemical natures, this augmentation of combustibility does not 

 combustible , ° , .. 1 



bv union with ta ke p.ace, and the combination of the two is less combustible 



alk. The lat- than that one of the constituents, which was the most so,because 

 an<i renders the one of them has lost exactly as much of its electropositive 

 sulph less neg. characters, as the other (the electronegative) has lost of its 

 more disposed characters ; and as in this case the effect must result from the 

 tooxigeu. sum of the affinities, it follows that the affinity of the most 



considerable is diminished in proportion as the quantity of the 

 An opposite other is greater, and its affinity for oxigen less. It is from this 

 te ct ' explanation that we may conceive a phenomenon of which £ 



shall give an account ; namely, that the oxide of tin mixed 

 with the oxide of gold, becomes reduced to the metallic state 

 without the addition of a more combustible body ; simply by 

 the action of heat, by forming a metallic alloy of gold and tin, 

 which is not decomposable by fire, even when fused with salt- 

 petre. 

 Heat rfiscom- Heat often produces, without the co-operation of other cir- 

 poses hodiesj cumstances, a decomposition of combinations -, and as in the 

 baby caloric electrochemical theory we form the conclusion, that nobody 

 may become can be restored to its original properties without the influence 

 restore the"" or " tn e same el j ctricity which it parted with when it entered 

 orijr. pro- into combination, we must likewise imagine as a consistent 

 SafticlV* f consequence of this fact, that in the same manner as the 



separate electricities, by their combination disappear and pro- 

 duce fire, so caloric in its turn, when accumulated and tending 

 to regain its equilibrium, is capable, in certain circumstance, of 



disappearing 



