Correction [to "Lipstik Condenser Microphone System," by J.K.Hilliard and J.J. Noble

An error in calculation has been brought to our attention by Clifford E. Berry of the Consolidated Engineering Corporation, Pasadena, CA, USA. The error appears in Fig. 4 of the paper, "Lipstik Condenser Microphone System," by J.K.Hilliard and J.J. Noble, on page 165 of the November-December, 1954 issue of TRANSACTIONS OF THE IRE, vol. PGA-2, no. 6. The correction has been made in a drawing showing open circuit RMS voltage produced by thermal agitation in the real component of the impedance of a parallel resistor and condenser, which should be substituted for the original Fig. 4.