Biospherics Inc. of Rockville said it moved into the black in the third quarter on the strength of increased profits throughout all three divisions.

The company, which provides high-tech products and services for the health, maritime and environmental industries, reported net earnings of $64,460 (1.7 cents per share) for the three months ended Sept. 30, compared with a loss of $2,961 for the same period a year ago.

The company said earnings for the year to date totaled $81,409 (2.1 cents), after earning $71,528 (1.8 cents) for the first nine months of 1984.

*Williams Industries, a construction company in Falls Church, reported that earnings dropped during the past fiscal year after a "severe cyclical swing" in the profitability of its main affiliate.

Net profits for the year ended July 31 amounted to $611,466 (38 cents per share), compared with $750,921 (53 cents) for the 1984 fiscal year, the company said yesterday.

Frank E. Williams, the company's president, said a major factor behind the 1985 profits figures was the change of fortunes of its affiliate, John F. Beasley Construction Co. Beasley suffered a small loss during 1985 after a strong year in 1984, when Williams' equity in Beasley's earning accounted for two-thirds of its total profits, the company said.

*Profits grew 27 percent in the third quarter at BDM International Inc., a McLean professional services firm that does much of its work for the Pentagon.

The company reported that third quarter net income totalled $2.6 million (26 cents per share), up from $2.1 million (21 cents) for the third quarter of 1984. Total revenue for the three months ended Sept. 30 was $63.7 million, up 30 percent from $48.8 million in the same period the previous year, the company said.

*W. Bell & Co., the jewelry retailer, said a sluggish retail environment and mounting consumer debt helped contribute to an 11 percent decline in sales for the first quarter and produce red ink on the balance sheet.

Sales for the 13 weeks ended Sept. 28 totaled $24.4 million, compared with $27.2 million for the same period a year ago, the company said. The company said it lost $255,900 (8 cents per share) for the quarter, after earning $145,800 (5 cents) in the first quarter of 1984.

*Radiation Systems Inc., which manufactures high-technology antenna products for the military and other markets, said earnings slowed slightly in the first quarter, though it said they should soon resume on an upward path.

The company reported earnings of $783,000 (17 cents per share) on sales of $7.3 million for the three months ended Sept. 30. For the same period a year ago, the company earned $970,000 (22 cents) on sales of $7.2 million.

*United Financial Banking Cos. said earnings grew 85 percent in the third quarter, rising from $164,981 (26 cents per share) in the third quarter last year to $305,126 (48 cents) this year.

For the nine months ended Sept. 30, the bank-holding company's earnings totaled $746,062 ($1.18), compared with $519,350 (82 cents) for the same period in 1984. As of the last day of September, the bank's assets were $53.9 million, while liabilities stood at $46.4 million.

The company, which runs the Business Bank in Northern Virginia, said gains of $310,872 from the sale of investment properties contributed to the earnings growth.

*Eastmet Corp., a troubled Baltimore steel manufacturer, reported losses of $4 million (79 cents per share) in the third quarter, compared with $8 million ($1.58) for the same period a year ago. The company said the improved performance presages a return to profitability in 1986.

*The Washington Gas Light Co. reported a decline in profits for the 1985 fisal year, citing lower therm sales because of warmer weather.

For the year ending Sept. 30, the company said net income applicable to common stock totaled $38.1 million ($2.35 per share), compared with $38.5 million ($2.52) for the previous year.