( 533 ) 



mixtures was oriuiiiallv loii;^^ M) ctti. and divided in niiri.'s, had an 

 inner hore of about 2.(5 nun., an outer Itore of aboul 7 mm. 



The celalion of the bores of the urathiated |)ar(s of the irianometer 

 tul>e and the e.xperimental tube at dilferent phiees was determined 

 In repeatedly moving a mereury eohimn of alK)ut 10 em. length 

 over 5 em. and then measuring its length. To etfeet this the manometer 

 tube was |dae(Ml in a horizontal position and the places of the ends 

 of the mercury column were read with an eye-glass. We avoided 

 parallax by taking care that the nearest graduation on the glass 

 should be seen to cover its image on the mercuiT. For the wider 

 experimental (tilx; this method coidd not l>e used owing to the 

 cliange (d' form of the mercury meinscus at the ends of the column 

 in conseipience of gravitation. Therefore the experimental tube was 

 provided Avith a glass cock to which a narrow glass capillary luul 

 been connected. From this the air escai)ed only slowly under the 

 excess of pressure of 10 cm. mercury. Then the tube was placed 

 verticalh' after a mercury column of the length mentioned had 

 been admitted. The latter could each time easily Iw moved over 5 

 cm. and the })osition of the ends read. 



Then a longer mercury column was admitted iido the tube in order 

 to derive the mean bore from its weight. The bore of the above 

 mentioned tube under the great reservoir (/'J, and also the volume of 

 the reser\oir were then determined by weighing the merciuy. 



§ o. As an instance of the [)rocess of the calibrations and the 



TABLE I. 



35* 



