in the Magnetic Field. 



279 



The proportions selected for the reaction of nitric acid on 

 iron were 70 c.c. HNO s and 30 c.c. H 2 acting on two grams of 

 iron. The speed of the reaction without the field was found to 

 vary in a marked manner with the initial temperature. Brisk 

 effervescence of hydrogen occurred, neither accompanied nor 

 followed by the production of nitrous fumes. The effect of the 

 magnet was to greatly increase the speed, reducing the average 

 time from about eight minutes to less than one minute. Red 

 fumes always resulted from the reaction within the field. 



To change the character of the ordinary reaction, at any 

 moment, it was only necessary, as in the case of the reaction 

 with aqua-regia, to bring the magnet into function. The pro- 

 duction of nitrous fumes, as in the former case was always 

 accompanied by a new rise of temperature, although to a 

 smaller extent than in the aqua-regia reaction. 



Table III and curves "f " "g" "h" and "i" figure 2 show, the 

 range of temperature during the reactions with nitric acid. 

 The variations of speed caused by slight changes in initial tem- 

 perature were very marked. A comparison of the total amounts 

 of heat produced within, and outside the field cannot be de- 

 duced from these curves because of the very different speeds 

 of reaction. 



Table III. — Action of nitric acid upon iron. 





Temperatures. 



TIME. 



Tempebatures. 



TIME. 



Magnet 

 not 



Magnet 

 not 



Magnet 

 not 



Magnet 



Magnet 

 not 



Magnet 

 not 



Magnet 

 not 



Magnet 





acting. 



acting. 

 "fir" 



acting- 

 "h" 



"i" 







acting. 

 "/" 



acting. 

 "ff" 



acting. 

 "h" 







"/" 



"i" 





o 



o 



o 



o 



o 







o 



m 00 s 



25-85 



26-50 



27-25 



24-90 



^m 



30 s 



39-45 



44-95 



49-45* 





30 



29-65 



2990 



34-75 



52-50 



8 



00 



40 18 



46-10 



49-37f 





1 00 



30-50 



31-60 



35-90 



52-80 



8 



30 



40-90 



47-00 



51-00 





1 30 



31-05 



32-55 



37-20 



52-50 



9 



00 



41-70 



48-00 



51-18$ 





2 00 



31-92 



33-00 



38-25 





9 



30 



42-58 



48-95 



50-90 







2 30 



32-55 



33-80 



39-45 





10 



00 



43-35 



49-90 







3 00 



3319 



35-00 



40-70 





10 



30 



44-30 



50-45 











3 30 



33 92 



3610 



42-10 





11 



00 



45-00 



50-75 









4 00 



34-58 



37-50 



44-35 





11 



30 



45-65 



51-00 







4 30 



35-30 



38-70 



46-72 





12 



00 



46-18 



50-95 









5 00 



36-05 



40-10 



47-72 



.. 



12 



30 



46-55 



... 







5 30 



36-68 



40-90 



48-45 



.. 



13 



00 



46-75 



... 











6 00 



37-38 



41-90 



48 97 





13 



30 



45-95 













6 30 



38-15 



42-90 



49-22 





14 



00 



46-95 











7 00 



38-80 



43-90 



49-40 



















* First maximum. f Magnet thrown into action. % Second maximum. 



Ill — Experiments with Hydrochloric Acid and Iron. 



70 c.c. of the concentrated acid diluted with 30 c.c. of water 

 were allowed to act upon two grams of iron. The rise of tem- 

 perature was much smaller than in the determinations with aqua 



