CHAP. XII.] TELEPHONE. 361 



essential constituents of the image of Him who in the 

 beginning created, not only the heaven and the earth, but 

 the materials of which heaven and earth consist. 



In 1875 he read before the Chemical Society a 

 paper " On the Dynamical Evidence of the Molecular 

 Constitution of Bodies." 



The lecture on Thermodynamics at the Loan 

 Exhibition of Scientific Apparatus in London in 1876 

 (to which he had contributed his real-image Stereo- 

 scope, etc.), was illustrated by his own model of the 

 Thermodynamic Surface. 1 



The last of his public lectures was the Eede 

 Lecture " On the Telephone," delivered at Cambridge 

 in 1878, and illustrated with the aid of Mr. Gower's 

 Telephonic Harp. 



After pointing out the extreme simplicity as well 

 as the absolute novelty of the invention, lie made it 

 the text of a discourse which is remarkable both for 

 suggestiveness and discursiveness. 



I shall . . . consider the telephone as a material symbol 

 of the widely separated departments of human knowledge, the 

 cultivation of which has led, by as many converging paths, 

 to the invention of this instrument by Professor Graham 

 Bell. 



... In a University we are especially bound to recognise 

 not only the unity of Science itself, but the communion of 



1 See Part II. In the official handbook to the collection, the 

 articles entitled " General considerations respecting Scientific Appar- 

 atus " and " Molecular Physics," were written by Professor Maxwell. 

 When her Majesty the Queen visited the collection Professor Maxwell, 

 at the invitation of the Lords of the Committee of Council on Educa- 

 tion, attended as the representative of Molecular Physics. 



