1923] Proceedings of the Elisha Mitchell Society 37 



cess. The lecturer accompanied his talk by moving pictures. These 

 showed first the difficulties and trouble consequent upon the old sand 

 mold method of making cast iron pipe, which has been in use for over 

 two centuries, the first cast iron pipe having been laid to supply the 

 fountains of Versailles in the time of Louis XIV, Until about ten 

 years ago no improvement had been made in this process. 



The new centrifugal process consists of a cupola, a revolving, 

 water-cooled molding machine, an annealing furnace, and a dipping 

 vat. The ladle discharges its contents into a cantilevered water-cooled 

 trough, which projects into the interior of the revolving mold, and 

 from the forward end of which iron is discharged in a stream parallel 

 with the plane of revolution. The machine includes a hollow cylin- 

 drical mold, revolved by a water-wheel. The mold is enclosed, and 

 travels back and forth on inclined ways. The mold rotates at 1600 

 revolutions per minute, and a complete pipe is poured, cast, and 

 cooled sufficiently to take from the mold in three minutes. 



From the mold the pipe goes to an annealing furnace and thence 

 to a dipping vat to re-coat it with tar. 



.The centrifugal pipe is lighter (per foot), denser, thinner, and 

 much stronger than the pipe cast by the old process. 



264th Meeting— April 10, 1923 

 Archibald Henderson — Einstein's Finite, Unbounded Universe. 



The classic theory of Newton presumes that the universe is in- 

 finite in extent, and that the mean density of matter is infinitesimally 

 small. This theory makes our "island universe," which by constant 

 loss of radiation and stellar matter, is a gradually dying universe. 

 In the effort to arrive at a more satisfactory conception, in accordance 

 with the General Relativity Theory, Einstein examines various hy- 

 potheses on the assumption of an infinite universe; and was com- 

 pelled to reject them. Finally on the assumptions: (1) the mean 

 density of matter was an appreciable quantity, (2) that the universe 

 was finite but unbounded; and (3) that the matter in the universe 

 was virtually at rest (as compared with the velocity of light), Ein- 

 stein on the basis of the General Relativity Theory concluded that 

 the space in which we live was "spherical" in the Riemann sense. 

 He found the radius, volume, mass, and weigiit of the material uni- 

 verse in terms of the presupposed (value unknown) value of the 



