186 TRANSACTIONS OF THE [MARCH 15, 



upon another only through the aid of a third, which maintains 

 its identity at the close of the reaction, yet is known to be de- 

 composed and recom]-»osed successively throughout the operation. 

 By heating a relatively small quantity of cobaltous chloride Avith 

 bleaching powder, the latter is wholly decomposed, yielding cal- 

 cium chloi-ide, water, and oxygen, yet at the close of the reaction 

 the cobaltous oxide is found unaltered. It has been shown that 

 it is successively decomposed and recomjioscd during the opera- 

 tion. In their investigation on "Simultaneous Oxidation and 

 Reduction by means of Hydrocyanic Acid," Profs, Michael and 

 Palmer" consider it probable that many of the most important 

 reactions of animal and vegetable life are due to the intercession 

 of substances which undergo change during the reactions, and in 

 the end return to their original form. They suggest also that 

 some of these reactions seem to be dependent on substances ca- 

 pable of decomposing water into its elements, or into hydrogen 

 and hydroxyl ; and when the chemist can command a reagent 

 possessing that propej'ty at a low temperature, their imitation in 

 the laboratory may follow its discovery. 



(9.) Thnt chemically pure zinc is not soluble in dilute sul- 

 ])huric acid has been known since Faraday's day; tliat sodium 

 does not combine with perfectly dry chlorine, even if the metal 

 be heated to its fusing-point, was shown by Wanklyn^* in 1869 ; 

 more recently, Mr. Cowper has found that dry chlorine does not 

 attack Dutch metal ; six years ago, Mr. 11. B. Dixon " demon- 

 strated before the British Association that a well-dried mixture 

 of carbon monoxide and oxygen can be subjected to the electric 

 spark without exploding. In March, 1885, Mr. 11. B. Baker °' 

 communicated to the London Cliemical Society results of his 

 experiments on the influence of moisture in the combustion of 

 carbon and of phosphorus in oxygen, his conclusions being that 

 the combustion of dry charcoal in dry oxygen is incomplete and 

 slower than in ordinary moist oxygen. In the discussion which 

 followed Mr. Baker's paper, Dr. Armstrong pointed out the im- 

 portance of these new facts in defining more accurately concep- 

 tions of chemical action, and suggested that cliemical action is 

 '' reversed electrolysis." In his address as ]n-csident of the 

 chemical section of the British Association for the Advancement 

 of Science (Sept. 10, 1885), Dr. Armstrong further discussed 

 this subject, and stated that the idea conveyed by the expression 

 "reversed electrolysis" is found in the Avritings of Faraday, 

 neglect of whose teachings retards the progress of chemistry. " 



The influence of low and of higli temperatures in retarding 

 and facilitating chemical changes is fundamental, but some phe- 

 nomena not generally known may be appro])riatcly mentioned. 

 Victor Meyer and Langer " have shown that whereas chlorine 



