CHEMISTRY. 



By GEORGE F. BARKER, 



Professor of Physios in the University of Pennsylvania, Philadelphia, 



GENERAL. 



Among the interesting Chemical papers of the year we 

 note one by Berthelot on certain chemical phenomena pro- 

 duced by the electricity of tension. In these experiments a 

 Holtz machine was employed, one electrode of which was 

 connected by means of a platinum wire with the internal 

 coating of a sealed tube containing the substance to be act- 

 ed on, the external coating being connected with the inter- 

 nal one of the next tube, and so on, the second electrode of 

 the machine being put in communication with the last outer 

 coating. No spark can possibly occur within the tubes, 

 though they are incessantly charged and discharged, but 

 always with the same kind of electricity. He finds that 

 ozone is formed from oxygen equally well by positive or 

 negative charges, though the amount produced is increased 

 with the tension, being five or six per cent, for sparks one 

 centimeter long, while with sparks of half a millimeter only 

 one or two thousandths is formed. No production of nitrous 

 compounds was observed with a mixture of nitrogen and 

 oxygen. Acetylene was formed in quantity when organic 

 vapors were placed in the tubes. Nitrogen was freely ab- 

 sorbed by organic bodies such as paper and dextrin. Ex- 

 periments are in progress to determine the cause of the spe- 

 cial action thus exerted. 



Terreii has published an extended paper on Dulong and 

 Petit's law of atomic heats, in which he compares together 

 the products of specific heat and atomic weight of bodies in 

 the state of vapor, and finds a close accordance with the 

 law. He asserts that a body not gaseous has a specific heat 

 twice that which the same substance possesses in the gaseous 

 condition. 



Victor Meyer has described an improved form of appara- 



