XXIV. ABSTRACT OF PROCEEDINGS. 



Minkowski used the relations of Einstein and showed that if 

 time be added as a fourth dimension to space the two observers 

 would record the event alike in this four-dimensional world. Space 

 and time are thus, as it were, ideas introduced by the observers,, 

 the only reality being a blend of the two; various observers resolve 

 the real world differently into space and time, just as the vertical 

 direction differs for people who live in different latitudes. 



Einstein subsequently generalised his theory so as to apply to 

 all types of motion. He showed that it is impossible to distinguish 

 between a permanent field of force such as gravitation and a 

 certain peculiar type of motion; in fact, by choosing suitable axes 

 of reference gravity can be disregarded, just as the traveller inside 

 the projective described by Jules Verne regarded the contained 

 bodies as being without weight. 



By making use of this equivalence and by using the conception 

 of a four-dimensional. world Einstein succeeded in expressing the 

 law of gravitation as a relation between space, time and mass. 

 From this relation he deduced that space and time in the vicinity 

 of matter are slightly distorted so that the ordinary propositions 

 of Euclid are no longer strictly valid. The space in the vicinity 

 of matter has many points of resemblance to the space imaged in 

 a slightly convex mirror. Tn particular a ray of light which 

 moves in a straight line when distant from matter is slightly bent 

 when passing near a large mass such as the Sun. Einstein calcu- 

 lated the deflection to be expected and his prediction was verified 

 by the published results of the British Astronomical Expedition 

 to Brazil in connection with the solar eclipse, 29 May, 1919; this 

 deflection was twice that calculated on the Newtonian view that 

 light consists of corpuscles or minute bodies. 



There will be an Astronomical Expedition to Australia to 

 observe the solar eclipse occurring in September, 1922, and it is 

 confidently expected that further valuable information will be 

 obtained. 



