00310cam a22001097a 4500008004000000082001300040100001700053245004500070260004200115300001400157650002900171180718b1949   xxu||||| |||| 00| 0 eng d  aYA1 B456  aBernal, J.D.  aThe freedom of necessitycby J.D. Bernal  aLondonbRoutledge and Keganpaulc1949  axi, 437p.  aScience and civilization