60 



density. If one might presume on such a point, I should say that 

 the high parts of the earth are made of something light. The 

 heavy dense parts are those covered by considerable quantities of 

 water, and they have sunk deep into the centre of lava, in which I 

 conceive all things to be resting. 



I come now nearly to the end of my theory, and I will show 

 you what you will think is an absurd representation of what 

 I consider the earth to be. Here is a diagram of the earth. 

 See Plate. You will remember that everything here is 

 exaggerated ; it is not intended to be a correct representation. 

 It is a caricature, and a caricature of the most extravagant kind ; 

 but if it conveys to you the broad ideas which have impressed 

 themselves on my mind, it will be doing the right thing. It will 

 only be expressing what I really think about the broad characteristics. 

 I do think that a large proportion of the central part of the earth 

 is fluid and hot, and I think that upon this there are resting divers 

 classes of something like solid matter, — how many I cannot say, 

 but it is enough for my purpose to take two. The deep black I 

 take to be heavy rock ; and the fainter black is lighter and floats 

 lightly ; and all the rest of blue-green colour is sea. There are at 

 various places cracks or chinks where volcanoes break out. At some 

 places where the crust of the earth is thin you can have two or three 

 volcanoes close together, as in Europe we have Etna, Stromboli, 

 and Vesuvius. So that, in this figure, absurd as it may seem, I 

 have condensed, to the best of my conjectural power, my suppos- 

 ition as to what the state of the earth really is ; and if anybody 

 chooses to find fault with it, I will not quarrel. I give it as a sort 

 of inference from the number of things I have said. My lecture is 

 terminated, and I only hope that those of my audience who have 

 not fully caught my words, or have in other ways failed to under- 

 stand me, will come up and speak to me. 



( This Lecture mas taken dcnvn by short-hand reporters and subsequently 

 revised by the lecturer. ) 



