182 



MR. W. THOMSON ON THE CONSTRUCTION OF 



vessel thus closed, was afterwards found to remain free 

 from fungus-life for any lengtli of time. Having thus 

 been successful by such a rough arrangement in preventing 

 the entrance of fungus-spores, I next decided to try the 

 same experiment on a rougher and larger scale, and con- 

 sequently had the rough model made which I show here 

 this evening [see figure] . 



Each side of this box or room is made of thin layers of 

 cotton wool sewn between two pieces of cloth, with a glass 

 (B) in front, which serves equally as door and window. 

 A conical-shaped arrangement (D) made of stout paper is 

 pasted to a square frame at its base, which fits against one 

 end of the room. The stem of an ordinary glass funnel (c) 

 is passed through the apex of this paper cone, and there fixed 

 by means of a piece of string. An india-rubber tube (F), 

 communicating with a pair of bellows, is put on the end of 

 the stem ; the large end of the funnel is covered with a thin 

 layer of cotton wool placed between two pieces of cloth and 

 fixed round the funnel-edge by means of an elastic band. 

 When the window at the other end of the room is opened 



