314 Scientific Intelligence. 



Professor Penfield in referring to Dr. Emmens' new min- 

 eral species blneite, in this Journal for June, 1S93, says: 



"Although it must be admitted that nickel is a rare con- 

 stituent of pyrite, yet nickeliferous pyrites are known, and at 

 Sudbury in particular where iron and nickel are so abundant 

 we might expect to find a mutual replacement of these ele- 

 ments." 



The notes here submitted show that nickeliferous pyrite is 

 found at Sudbury. In a similar way the many other iron- 

 nickel sulphides may be explained as minerals, in which the 

 isomorphous elements iron and nickel replace each other in 

 varying proportions. Doubtless this nickeliferous pyrite is a 

 purer form of the minerals described as whartonite and blueite 

 by Dr. Emmens. 



Laboratory of the School of Mining, 

 Kingston, Oat, February, 1S94. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Electric Conductivity of Flames. — Experiments 

 have been made by de Hemptinne to determine the electric con- 

 ductivity of flames and of gaseous mixtures at the moment of 

 union or of dissociation. The apparatus used consisted of two 

 electrodes of platinum, one connected with a voltaic cell and the 

 other with a capillary electrometer, so arranged that whenever a 

 conducting substance was brought between them, the mercury in 

 the electrometer became of lower potential and moved upward 

 in the capillary tube. When these electrodes were placed in a 

 mixture of nitrogen dioxide and oxygen gases in the act of com- 

 bining, no effect was perceptible even when the electromotive 

 force employed was 100 volts. The result was equally negative 

 when hydrogen bromide and chlorine, and hydrogen chloride 

 and ammonia, were employed. If the electrodes be placed in 

 the same relative portion of a Bunsen flame however where the 

 combustible gas contains variable quantities of an indifferent gas, 

 the hydrogen flame and the carbon monoxide flame are found to 

 conduct well, the conductivity increasing with the temperature. 

 The experiments on the conductivity of explosive mixtures at 

 the moment of explosion, showed that in the case of oxygen- 

 hydrogen and chlorine-hydrogen mixtures, there is decided con- 

 ductivity ; while in the case of oxygen-carbon monoxide, it exists 

 though in a much less degree. Moreover, although hydrogen 

 chloride and ammonia show no conductivity when uniting, at 

 ordinary temperatures, dissociating ammonium chloride conducts 

 fairly well ; as also does ammonium bromide. Vapor of amy- 



