classes ”’ fixed by the spring of 1917 the position of the co-ordinate axes while thcir orthog- onality is preserved. 610 In applying Euclidean geometry the space-concept of the ‘law of error” | oe ! In the more important than tubular penetration of gases in the University of Sheffield, England. Formerly Professor of Chemical Soc., vol. 5 (1924); Hl. Key, European Bankruptcy and Emigration (1924); E. S. Bellasis, River and Canal Engineering (London, 192 an ce (N )