Hartree Douglas R.. Calculating instruments and machines. The University of Illinois Press, Urbana 1949, ix + 138 pp.

HOWARD H. AIKEN, WILLIAM BURKHART, THEODORE KALIN, PETER. F. STRONG, and others (Staff of the Computation Laboratory of Harvard University). Synthesis of electronic computing and control circuits. The annals of the Computation Laboratory of Harvard University, vol. 27. Lithographed. Harvard University Press, Cambridge, Mass., 1951. Second printing, revised, 1952, ix + 278 pp. The numerical algebra of Boole's Laws of thought (193, VII 131(3), XVI 224(4)) is applied to the problem of design of electric circuits —with special reference to the inclusion of vacuum tubes and rectifiers, and to circuits useful as components of electronic digital computers. Compare Kalin's paper reviewed above (XVIII 345(3)). Noteworthy is the chart method for simplifying expressions of the algebra, referred to by Kalin (loc. cit.) and Quine (XVIII 280). ALONZO CHURCH