Show Heard By N. N Y Jury i NEW NEY YORK Dec 9 UP Robert Ul Robert j jE E E. Stripling chief investigator f fOr fOrthe for r j the house un-American un activities committee appeared Th Thursday as asa asa asa a surprise witness before the spy- spy probing federal grand jury Striplings Stripling's name had not been mentioned in the list lUst of witnesses scheduled to go before the jury on the fourth day of its renewed investigation of alleged Communist Communist Communist espionage Identity of Thursdays Thursday's jury witnesses witnesses witnesses wit wit- nesses had been closely guarded by government go sources who also were silent on progress of the in in- in Stripling was accompanied by Donald Appell an investigator for forthe forthe forthe the un-American un activities com com- Appell was one of the committee staff members who went with Whittaker Chambers to the latter's latter's latter's lat- lat ter's Maryland farm last week at atthe atthe atthe the time Chambers revealed the microfilms of vital government documents hidden in a hollowed- hollowed out pumpkin Also waiting to testify were the Hiss brothers Alger and Donald and three F FBI B I agents |