ABSTRACT OF PROCEEDINGS. xliii. 



interest in the sky — principally southern constellations, 

 were described. Then the planets were described, their 

 size, revolution and distances from the Sun ; the features 

 of the inner planets, the asteroids and their origin, and 

 then the outer belt of the great planets and their probable 

 present state. The probability of life in each was explained 

 and reference made to the conditions of such life, if it 

 existed, and the nature of it. The lecturer stated that it 

 may be that beings specially created for such conditions are 

 so placed, but certainly no beings constituted as we are, 

 could exist in many of them. 



Abstract of the Fourth Popular Science Lecture 1904, on 

 "The Steam Engine and its Modern Rivals," by S. Henry 

 Barraclough, b.e., m.m.e., Assoc. M.inst. c.E., Lecturer in 

 Mechanism and Applied Thermodynamics, University of 

 Sydney. The introductory portion of the lecture dealt 

 with the question of mechanical energy or motive power 

 as being always one of the great necessities of the human 

 race, and its development therefore one of the chief func- 

 tions of the engineer. An outline was given of the various 

 available sources of power, and the methods adopted and 

 the cost of exploiting them, the two most important being 

 water-power and the potential energy in the immense 

 natural supplies of fuel. The remainder of the lecture was 

 devoted to a consideration of how the energy of the fuel is 

 made available by means of heat engines, and a brief sketch 

 was given of the thermodynamic principles underlying the 

 operation of all such engines — of which in the past the 

 ordinary reciprocating engine has been by far the most 

 important, but whose supremacy is in these latter days 

 seriously threatened by its modern rivals the gas engine 

 and the steam turbine. The attempts made to apply steam 

 to practical uses were described in outline from the time 

 of Hero (B.C. 200 or later) to Newcomen, whose "atmos- 



