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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 affinity 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. Crace Caxvert, 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. 
