338 Dr. Flight on the Thermo-electric 



stances, and the first instantaneous deflection of the needle ob- 

 served. A piece of bismuth was then substituted for the anti- 

 mony, and the experiment repeated. We ascertain from the 

 direction of the needle in this second experiment whether the 

 mineral in question lies between bismuth and antimony, or 

 beyond one of these metals in the series. Each mineral, in its 

 turn, was placed on the test-plate and treated in like manner with 

 the above two metals and the minerals which had been previously 

 examined till its position in the series was discovered. 



In this manner the substances mentioned in the folio wing- 

 Table were treated ; each one is electro-negative towards those 

 below it : — 



Red iron ore (two specimens from the same, locality examined). 



Copper pyrites, No. 1 (locality unknown). 



Copper pyrites, No. 2 (Worthing copper-mine, South Aus- 

 tralia). 



Galena. 



Iron pyrites., No. 1 (an irregularly shaped piece). 



Selenide of lead. 



Pyrolusite. 



Copper pyrites, No. 3 (Ram melsberg near Gosslar. Very pure). 



Psilomelane. 



Pitchblende. 



Manganite. 



Braunite. 



Copper pyrites, No. 4 (Dillenburg. Contains 27 per cent, 

 iron pyrites). 



Telluride of bismuth (Schemnitz, Hungary). 



Iron pyrites, No. 2 (a small cube). 



Melted copper pyrites^ No. 4. 



Peacock copper ore. 



Arsenical iron. 



Tinstone. 



Magnetic iron ore. 



Melted copper pyrites, No. I. 



Melted copper pyrites, No. 3. 



Bismuth (artificially prepared) . 



Melted copper pyrites, No. 2. 



Cobalt speiss. 



Meteoric iron (Atacama). 



Kupfernickel, No. 1. 



Nickel-antimony glance (Mussen near Siegen). 



Melted kupfernickel, No. 1. 



Kupfernickel, No. 2. 



Silver (artificially prepared. Chemically pure). 



