FORMATION OF INI - 



183 



to bring the surface of the liquid contained in it close to the 



g which ii thus made to hang down within the dish. 



When the apparatus is to be used, the spaces p p left between 



dges of t tnd the ledges ii are closed as tightly 



as possible by means of flat plugs of wood, so as to cause the 



ut of air passing through the apparatus to sweep over 



itace of the liquid, and the front of the box is 



Fig. 1. 



(I by means of a frame j A /m covered with muslin and 

 sliding up and down in grooves fixed to the sides, which in I 



