\G5 



in the case of porous bodies, the attraction is feeble, and not 

 raised into the power of a definite grasp of a given quantity- 

 such as an equivalent, which is the case with a powerful 

 affinity forming a chemical compound. Large and watery- 

 masses lose their water slowly by the mere force of gravitation. 

 Strong mechanical action rises to an equality with feeble 

 chemical affinity. Weak chemical affinity sinks into an 

 equality with mechanical action. Charcoal absorbs gases 

 more eagerly under pressure, but by a removal of pressure 

 they are still absorbed ; so that the mechanical force is greater 

 than the weight of the atmosphere can control. There are 

 many cases in which these two forces, if they be two, meet. 

 This of the mercury and other metal is one case. The feeble 

 chemical afiinity is, I suppose, overcome by the powerful 

 mechanical force. The alloy with sufficient chemical affinity 

 remains, that with a weak affinity separates. The mercury 

 flows off following the law of liquids ; in like cases it flows off 

 like water flowing slowly from a moist porous mass like wet 

 clay. Instances from the feeblest to the most powerful affinity 

 might be given, showing that only when the power reached a 

 definite point did the law of chemical equivalents come in. 

 At the same time there is a definite point where surface action 

 ceases under certain conditions. 



These ideas have arisen partly from experiments on the 

 subject, which may some day be published. I believe they 

 explain the difficulties attending the attraction of masses 

 which seem occasionally to oppose the combination by atomic 

 weights. 



A Paper was read "On the Conductibility of Heat by 

 Amalgams," by Dr. F. Ckace Calvert, F.R.S., and Mr. 

 Richard Johnson. 



The method followed in the investigations described in this 

 Paper is the same as that detailed in their former Paper on 

 the conductibility of metals and alloys. 



