Electrification associated with Dust- Clouds. 485 



divided state. In the case of iron the results were the same, 

 whether filings or reduced iron was used. 



Table II. 



Metal. 



Charge. 



Remarks. 



Aluminium 



? 



+ 



V 



+ 



Strong. , 



5) 



Weak. 

 Very strong. 

 Strong. 

 Weak. 

 Strong. 



>) 



>»_ 

 Variable. 

 Weak. 



j> 

 Variable. 

 Strong. 

 Variable. 

 Very strong. 



Weak. 

 Strong. 



Antimony 



Cadmium 



Calci urn 



Cobalt 



Copper ... 



Iron 



Magnesium. 



Nickel 



Silver 



Tin 



Titanium 



Uranium 



Zinc 



Zirconium 



! Platinized Asbestos* . . . 



* Compare Asbestos, Table IX. 



The charges obtained on the clouds of dusts of metals and 

 non-metals are thus of a character opposite to those associated 

 with the ions of the elements when in solution, and from this 

 the inference was drawn that clouds of dusts from solid acids 

 should also be positively charged, and here again the in- 

 ference was strikingly substantiated, only one exception 

 being noted. The acids used are mainly organic ones, as 

 only solid acids could be used. 



Table III. 



Acid. 



Charge. 



Acid. 



Charge. 



Antbranilic 



+ 

 + 

 + 

 + 

 + 

 + 

 + 



Malonic 



+ 



+ 



1 



+ 

 4- 



i 



T 



4- 



+ 



l 

 1 



Benzoic 



Molybdic 



Boric 



Mobic 



Citric 



Oxalic 



Chromic 



Phthalic 



Feri'ocyanic 



Salicylic 



Gallic 



Sulphanilic 



ilippuric 





Metastannic 







The anthranilic acid was not tested as to its identity 

 the quantity was very small. 



as 



