NUS Corp. of Rockville yesterday reported a half-million-dollar drop in earnings for the second quarter, while Wapora Inc., and Pubco Corp. showed improved profits.

At NUS profits, fell from $711,000 (72 cents per share) a year ago to to $220,000 (22 cents) in the three months ended June 30. The company blamed, "softness in the availability of engineering design work and certain types of environmental and nuclear consulting assignments."

Revenues of NUS were off only slightly, from $11.9 million to $10.9 million for the quarter and were up by about $100,000 for the first half of the year to $22.2 million.

Earnings for the six months totaled $501,000 (51 cents), down from $1.2 million ($1.24).

Warpora Inc. of Chevy Chase showed a 70 percent jump in earnings, to $244,000 (37 cents) from $132,000 (22 cents) for its fiscal year ended June 30.

Revenues for the environmental consulting company climbed to $6.4 million from $4.4 million, mostly because of increased demand for environmental impact studies, the company said.

Pubco also reported a sharp up-swing in earnings. The Washington holding company has combined subsidiaries that are among the dozen largest commercial printers in the nation. Pubco earned $410,000 (15 cents) for the six months ended June 30, up from $252,000 (8 cents) a year ago.

Pubco said its sales increased to $26.9 million from $25.2 million for the first half, a 7 percent increase.

Pubco's chairman and president, Charles W. Lockyer announced that the company plans to sell about a million new shares of stock next month through a New York underwriter.

Washington Gas Light Co. said its common stock earnings for the 12 months through July 31 amounted to $11.2 million ($2.56 per share), down from $11.8 million ($2.71). Both figures reflect a change in accounting methods that added $1.01 to current profits.

Eliminating the effect of the change in accounting, earnings per share were off $1.16, which Washington Gas blamed on delays by the District of Columbia Public Service Commission in approving requests for higher rates.

Baltimore Gas and Electric reported its common stock earnings increased to $71.1 million ($2.28) for the seven months through July 31, from $67.3 million ($2.19) in the same period a year earlier. For the past 12 months, common stock earnings were $108 million ($3.48), up from $99.8 million ($3.25).

General Kinetics Inc. of Rockville said its net income for the year ended May 31 fell to $182,000 (23 cents) from $257,000 (34 cents) despite an increase in sales to $3 million from $2.7 million. General Kinetics provides magnetic tape maintenance services, makes tape equipment and electronic equipment cabinets.