1825.J M. Berxelius's Hypothesis of the Atomic Theory. 193 



slum and zinc, on the contrary, are electro-positive in regard to 

 all oxidated bodies, with respect to whose bases potassium and 

 zinc are positive. Hence acidity does not depend, as the anti- 

 phlogistic theory assumes, on oxygen as the acidifying principle, 

 but rather resides in the radical of the acid, and the oxygen 

 enters inditferently into the most electro-positive and electro- 

 negative bodies, or the strongest bases and acids. 



When the two electricities are separately manifested in any 

 body, they are concentrated in two or more opposite points or 

 poles, analogous to the poles of a magnetic needle. This elec- 

 trical polarity, of which the tourmaline furnishes a striking 

 instance, must also belong to the minutest particles of the body, 

 as well as to the whole mass, and this affords an easy solution 

 for all the phenomena of electro-chemical affinity ; for the dif- 

 ferent forces with which elementary bodies unite may be con- 

 ceived to depend on the different intensities of the electrical 

 polarities of their atoms. This hypothesis, however, is not 

 sufficient to explain why some bodies are electro-positive , and 

 others etectro-negdtive ; hni i^ we imagine the atoms of such 

 bodies to possess unipolarity, similar to that which Ehrman 

 observed in various substances, we may conceive that in the 

 atoms of electro-positive bodies, the electricity of the positive 

 pole predominates, and in those of electro-negative bodies, that 

 of the negative pole, and consequently these bodies will always 

 be in opposite states with respect to each other. 



The degree of affinity between different bodies cannot however 

 depend wholly on their specific unipolarities, but rather on the 

 intensity of the polarities generally ; for oxygen and sulphur, 

 both electro-negative substances, combine with much greater 

 energy than oxygen and copper, although the latter is an electro- 

 positive element; and the influence of temperature has a powerful 

 effect in modifying chemical attractions. 



" If these conjectures," says Berzelius, "present a correct 

 idea of the relations of bodies to electricity, it follows that what 

 we call chemical affinity is nothing else than the effect of the 

 electrical polarity of their atoms, and that electricity is the pri- 

 mary cause of all chemical action." 



But it is time to quit this part of the subject, and turn to that 

 which is more immediately the object of this abstract ; and first 

 we shall endeavour to explain the manner in which the relative 

 weights of the atoms of bodies are determined. 



(To be continued.) 



New Series, vol. ix. 



