l8 ANIMAL LIFE OF THE BRITISH ISLES. 



the familiar drawings in the books of Thomas Bell and J. G. 

 Wood, copied from French authors. 



Mr. Adams experienced great difficulty in making these 

 observations owing to the nature of the subject, but he perse- 

 vered, and made plans of sections from a hundred of the three 

 hundred hills he explored, and found that no two plans were 

 alike. Some were very simple, others exceedingly complicated, 

 " but," he says, " in no case have I found one to tally exactly 

 with the time-honoured figure originating from Geoffroy Saint- 

 Hilaire, elaborated by Blasius, and copied from him by every 

 succeeding writer, apparently without the slightest attempt at 

 verification." 



But even in those cases where there is some approach to the 

 plan of the old diagram, Mr. Adams found that it was clearly 

 not due to any scheme for constructing a baffling system of 

 bolt-runs for defensive purposes, but purely incidental to the 

 work of excavating the nest cavity and getting rid of the 

 material dug out. The easiest way to dispose of this redundant 

 earth is to push it to the surface, and to do this a tunnel has 

 to be made above the nest cavity. This, as a rule, is originally 

 only from two to six inches below the surface, but the hoisting 

 out of the surplus earth causes the formation of a solid dome of 

 considerable thickness above it. The tunnels thus made to get 

 rid of earth usually end in blind terminals, and would not be 

 available for escape in the case, say, of the " fortress " being 

 entered by a Weasel. It is notable that in the only one of Mr. 

 Adams' plans that approaches nearly to the old figure there is 

 no connection between the "galleries" and the nest cavity. 



In some soils (like the Bunter Sandstone) Adams found that 

 stones of four ounces are turned out that is, equal to the 

 average weight of an adult Mole. He also found that " the 

 softer the soil, as a rule, the nearer are the runs to the 

 surface." 



In his work " De la Taupe," de Vaux says : " The Mole 



