SUPPORT FOR FORD DECLINES SHARPLY
Gallup poll, commissioned by NY Times, indicates Pres Ford's decision to pardon former Pres Nixon and to consider pardons for other alleged Watergate conspirators has sapped his support among gen public; survey shows wide disapproval at least for timing of pardon, although there are indications that most of persons questioned in survey would not have opposed pardon for Nixon at a later time; survey shows 62% of those questioned disapprove of pardon to Nixon, 31% approve and 7% have no opinion; 32% of those questioned feel Ford is doing good job, 33% say fair job, 25% say poor and 10% have no opinion; Aug 16-19 survey results compared; other data (L)