( 331 ) 

 Hefore tlie cultivation O cc. , noniial KMiiü^ 



10 



After the cultivation 48.3 



At a second experiment 100 cc. consumed : 



Before the cultivation O cc. — normal KMnO*. 



After the cultivation 26.5 ,, ,, ,, 



Even this rough estimation gives the convincing result that much 

 organic matter is formed from the methan. Hence it follows that 

 methan is the starting point for the pi-oduction of a relatively rich 

 flora of microbes, which as said above, may even at an early period 

 contain amoebes and monads living from the methan bacteria. 



There can thus be no doubt but methan is, though indirectly, of 

 importance as a fish-food in tlie waters, as tlie said flora certainly 

 serves as such. 



Further investigations concerning tlie natural history of the methan 

 bacteria and the relation between the assimilated methan and the 

 amount of organic matter produced are in execution. 



H. Kaserer (Zeitschrift fur das Yersuchswesen in Oesterreich, 

 Bd. 8 p. 789, 1905) seems also to have observed bacteria living 

 on methan, but he gix'es no particulars. 



Microbiologic Laboratory 

 of the Technic High School at Delft. 



Physics. — ''Determination of tlie TnoMso^-efect in mercury.'' By 

 C. ScHOUTE. (Communicated by Prof. H. Haga.) 



This determination has been executed as a sequel to that, undertaken 

 by Prof. H. Haga, and published in the "Annales de I'Ecole Poly- 

 technique de Delft, I, 1885, p. 145; HI, 1887, p. 43." 



A detailed account of the way, in which the experimeids were 

 carried out, has been given in my "Dissertation". The results 

 mentioned here were partly obtained afterwards. 



The value of the TnoMSON-constant was expressed by a relation, 

 got by integration of the differential equation, which Verdet has 

 given for the points of an unequally heated homogeneous conductor, 

 when an electric current passes through it. 



If the distribution of tempeiature is considered, after it has grown 

 constant, and in some portion of the conductor, confined by two parts 

 of a constant temperature, this equation is integrable, and the integral 

 is quite simple for the points halfway between these lindts of constant 



