APPENDIX 293 



placed in the saucer are very minute, i.e. of very low 

 temperature (estimated when " boiling " by Prof. Dewar 

 at a temperature 190 C.). These molecules imme- 

 diately begin to expand by the absorption of Ether. 

 To get this Ether something must be robbed of Ether. 

 This something is firstly the atmosphere surrounding 

 the boiling air which is chilled, and secondly the glass 

 of the upper part of the receiver. The latter become 

 so cold that the gaseous objects atoms or molecules 

 inside the receiver become attracted to the bottom of 

 the dished part of the receiver (a), they give Ether 

 to it which is seized by the liquid air molecules to 

 permit them to become gaseous, and thus a current 

 of Ether is set up and the whole of the gaseous objects 

 inside the receiver lose Ether and become solid. 



Two remarkable experiments may be noticed. One 

 with the element Chlorine (a faint yellowish green gas, 

 deep green as a solid) has the following reactions : 

 Directly the air has " boiled " away the saucer imme- 

 diately begins to return to the temperature of the 

 atmosphere which was the temperature before the 

 experiment was made, hence the upper part of the 

 receiver again seizes the Ether from the atmosphere 

 and chills it. As it returns to the normal tempera- 

 ture, the solid Chlorine seizes the Ether from the 

 dished part of the receiver and returns to the gaseous 

 condition, but before doing so passes from the solid 

 into the liquid form. It falls from beneath the 

 dished part of the receiver drop by drop, as illustrated 

 in fig. 6, and then from the liquid the Chlorine becomes 

 gaseous. Thus the cycle of changes is complete. 



With the element Bromine (which in the gaseous 

 state is red and a deep red solid) there is not the 



