specific and Latent Heat of Vaporisation. 5 



nected by means of rubber tubing with a steam boiler. The 

 steam passed up through B, down between B and A, and out 

 through i\I. After the first minute the flow of steam was 

 slackened so that very little came out either at M or O. 



In the first experiments M was connected with a long glass 

 tube, which carried the waste steam to some distance from 

 the instrument and balance. The steam or vapor escaping 

 through O was removed by the method adopted by Bunsen ; 

 a tube was set with its opening at right angles to O, and led 

 to an iron chimney in which a gas flame was kept burning. 

 In this way an air current was formed, which prevented any- 

 thing from rising to condense on the balance above. After 

 about five minutes the weight of the carrier and substance 

 with the water condensed was determined, and this was 

 repeated at intervals of five minutes for some time. 



It was found that with a good conducting substance the 

 weight found at the end of ten minutes could be taken as 

 correct, as after this there was little increase, and that proba- 

 bly due to condensation on the suspending wire. 



The regulation of the flow of steam was attended with 

 some difficulty : the least irregularity caused in the end an 

 increase of weight. Where the regulation was attempted, as 

 at first, by turning down the flame under the boiler, the blow- 

 ing aside of the small flame during a few seconds spoiled 

 several experiments. 



With the complete apparatus, provided with taps and con- 

 denser, this difficulty was not felt, as the gas was full on the 

 whole time. 



199 



