An attempt has been made to measure the rate of change of superconducting transition temperatureTc, as a function of surface charge density &sgr;, in tin films. For films having thicknesses of 190, 670, and 1460 Å, |dTc/d&sgr;| was found in all cases to be less than 30 deg cm2C−1, the limit of sensitivity of the present apparatus. This negative result is compared with Glover and Sherrill's finding that in a tin film 70 Å thick,dTc/d&sgr; = −460 deg cm2C−1.