in the Magnetic Field. 273 



in abstract,* brought out other and unlooked-for modifications 

 of the reactions.f These have been further investigated and 

 are to be described in the present paper. My first experiments, 

 the sole object of which was to detect differences in the heat of 

 chemical action within and outside of the magnetic field, were 

 conducted in the following manner. Between the poles of a 

 small electro-magnet, with half inch core, was placed a beaker 

 containing a known amount of acid. The temperature of the 

 acid was indicated by a thermometer divided to fifths of a de- 

 gree centigrade. A weighed quantity of powdered iron was 

 introduced and the rise of temperature was noted at short inter- 

 vals of time until the reaction was complete. The movement 

 of the thermometer during repeated trials, in which all condi- 

 tions remained the same, excepting that in alternate experi- 

 ments the electro-magnet was active and inactive, served to 

 bring out its influence upon the speed and character of the 

 reaction and upon the amount of heat produced. 



The conditions were varied as to initial temperature, nature 

 and strength of the acid used and relative amounts of iron and 

 acid. In the following detailed account, the various determi- 

 nations are described in the order in which they were made. 



I. Experiments with Aqua-regia and Iron. 



Nitric and hydrochloric acids were mixed with water in pro- 

 portions which ensured rapid and complete solution of iron 

 without the application of heat. A suitable combination was 

 found by trial to consist of 4 vols. HC1, 3 vols. HN0 3 and 2 

 vols. H 2 0. The acids were the usual concentrated " chemically 

 pure" acids of commerce. 50 co of this mixture were allowed 

 to act upon two grams of powdered iron of the kind known as 

 " iron by alcohol." 



The electro-magnet,, already described, was placed, poles up- 

 permost, in a glass jar and surrounded with dry sand in order to 

 prevent any heating effect from the coils. A beaker holding 

 250 c. c. was placed directly upon the poles of the magnet. A 

 large bell jar, through the neck of which were set the ther- 

 mometer and an open glass tube, was placed over the jar con- 

 taining the magnet in such position that the bulb of the ther- 

 mometer dipped in the acid within the beaker. 



* A Preliminary Note on the action of Acids on Iron in the Magnetic field : 

 Proceedings Am. Association for the Advancement of Science, 1884. 



f This appears to be an almost unworked field. Professor Ira Remsen, in his 

 interesting paper on the '' Deposition of Copper on Iron in the Magnetic field" 

 (American Chemical Journal, vol. iii, No. 3, 1881), has furnished the earliest pub- 

 lished evidence of the influence of magnetism upon chemical action. More re- 

 cently the same author has announced the resumption of his experiments upon 

 this subject (Science, vol. i, No. 2, and American Chem. Journal, vol. vi, No. 6. 

 1885.) 



Am. Jour. Sci. — Third Sbries, Vol. XXXI, No. 184. — April, 1886. 



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