B 4 Thursday. February  
1 he U.S. Postal Service yesterday reported that for the fourth straight four-week period this fiscal year, its finances are in the black.</br></br>Postmaster General William F*. Bol-ger, speaking before the monthly meeting of the postal service board of governors, said that for the last four-week period he had expected a $3.2 million loss instead of the $1.7 million profit. The postal service accounting procedures use four-week periods.</br></br>During the first, quarter of this year, the postal service had profits of $163 million compared with $367 million last year. Blamed for the lower earnings were a 6.8 percent increase in personnel costs and 24.3 percent rise in transportation charges, which was higher than postal officials had expected, they said.</br></br>Last year the postal service earned $470 million, the first profit earned by the postal system since the end of .World War II. Bolger said yesterday, however, that he still expects the postal service to have a deficit by the end of the year.</br></br>The board of governors was expected to discuss yesterday whether to implement the proposed electronic mail system, but the governors recessed until Feb. 22 when the subject will be taken up again, postal officials said.