264 



being determined by the nature of the metals and the differ- 

 ence of their temperatures. 



IV. If two different metals be at the same temperature 

 throughout their mass, whether it be high, low, or mean, 

 contact will not produce deflection. 



V. (1). Sometimes the deflective energy, developed by 

 attrition of two metals at unequal temperatures, is more effec- 

 tive than that produced by their contact when their tempera- 

 tures are in a state of inequality to the same amount as that 

 at which attrition took place. (2). And sometimes the de- 

 flective energy of two metals in contact, at unequal tempera- 

 tures, is more effective than that developed by their attrition 

 when their temperatures are in a state of inequality to the 

 same amount. The result 2 is of less frequent- occurrence 

 than the result 1. 



VI. The deflection producible by contact of two metals 

 which are at unequal temperatures may be on the same side 

 with, or on the opposite side to that producible by attrition 

 of these metals when they are in a state of equality of tem- 

 perature. 



VII. When two metals at unequal temperatures produce 

 deflection on the same side of the magnetic meridian, both by 

 their attrition and contact, while, if their temperatures be 

 equal, their attrition causes deflection on the opposite side of 

 the magnetic meridian, it is an obvious consequence that the 

 deflection caused by attrition or contact of the metals, while 

 their temperature is unequal, will change to the opposite side 

 of the magnetic meridian, if attrition be employed during 

 the period of their approach to and arrival at equality of 

 temperature. 



VIII. If the two metals, being at unequal temperatures, 

 produce by their contact a deflection on the side of the mag- 

 netic meridian opposite to that which attrition under the same 

 circumstances affords, but synonymous with that which is pro- 

 duced by attrition when both metals are in a state of equality 



