What was going on when I was born?

In 1927, two French brothers lowered an electrical probe down an oil well on a wire and made a discovery as valuable as oil itself. Conrad and Marcel Schlumberger, who had been experimenting with using electricity to prospect for minerals, found that they could measure the electrical resistance of rock formations at various depths to obtain a picture of the underground geology. That process, known as well-logging, is now indispensible in drilling for oil, and highly profitable Schlumberger Ltd. has been the dominant company in the industry, with a 65 percent worldwide share of a $2.9 billion-a year business that is growing at more than 30 percent a year. Yet Schlumberger, which says it is not a well-logging company, is trying to expand its reach into what it considers is its actual field - data collection and processing.

MINNEAPOLIS BORN with a defective ability to form pigment, albinos are conspicuous people. Their whitish hair and skin and pale, squinting eyes often cause them to suffer more from social stigma than from their actual physical disabilities. In the hope of someday allaying the social and physical handicaps of albinos, scientists at the University of Minnesota are unraveling the intricacies of pigment formation, looking for an understanding that may help them correct the genetic flaws that cause the disorder. These defects afflict about one in 20,000 Americans, with the frequency higher in blacks than in whites. In all albinos, there is an absence or shortage of melanin, the pigment in skin that protects underlying cells and blood vessels from damage by ultraviolet radiation.

Inventories rose 1.1 percent for American manufacturers, wholesalers and retailers in July, the Commerce Department reported today, in a new indication of weakness in the national economy. Sales for July rose less than one-tenth of one percent and, as a result, the inventory-to-sales ratio climbed to 1.41, the highest level since last September's 1.43. The ratio means that it would take 1.41 months to sell off inventories at July's sales pace.

International Charges that toxic chemical weapons were used by the Soviet Union and the Vietnamese in Southeast Asia and possibly Afghanistan in violation of international agreements were backed up with evidence produced by the State Department. The evidence, which the department termed ''significant, although preliminary,'' relied heavily on analysis of one leaf-and-stem sample collected in Cambodia near the Thai border. (Page A1, Columns 1-2.) Russians will have to pay more for gasoline, vodka, jewelry and other ''nonessentials,'' the head of the State Committee on Prices announced. In explaining the increases, Nikolai T. Glushkov, said ''corrections'' in some prices were necessitated by ''conditions of production, the growing cost of the extraction of raw materials and the need to ensure the rational use of resources and certain commodities.'' Mr. Glushkov said the cost of ba sic foods would remainthe same and some commodities, such as medici nes, would be reduced. (A1:1.)

''Wouldn't it be funny,'' the White Plains woman said to her husband while ''antiquing'' Aug. 18 in Bucks County, Pa., ''if I found some of the jewelry I lost in the burglary?'' To her surprise, she did - a custom-made amethyst bracelet stolen, along with at least 75 other jewelry and silver pieces, only 10 days earlier from their home near the Scarsdale border. The thieves even took their tennis bags - presumably to carry the loot -but not their racquets. Arrest Follows Discovery On Aug. 20, using the couple as decoys, Manhattan detectives of the Special Frauds Squad arrested a previously convicted Bowery fence. They seized jewelry and silver estimated at nearly $500,000, including a dozen pieces the couple said were theirs.

CAMBRIDGE,Mass. FOR decades, B. F. Skinner has written about and preached his behavioral theory of human psychology. Thoughts, emotions and actions, he contends, are exclusively products of environment; free will, according to the Harvard University psychologist, simply does not exist. He envisioned utopian societies, and described one in his book, ''Walden II,'' that resulted from tightly controlled systems in which people were motivated solely by the manipulation of what he called positive and negative reinforcements. Now, at the age of 77, Dr. Skinner is conceding that behavioral psychology may be unable to significantly improve the collective human condition. He said in an interview at his office that 10 years ago, when his book ''Beyond Freedom and Dignity'' was published, he believed behavioral ps ychology provided the ''technology'' to solve the world's probl ems. But he hadn't thought through, he says, ''the question of w hether people would ever have the inclination'' to use this tool.

President Reagan ran into trouble today from Congressional leaders of his own party as he sought to build a legislative coalition to pass a second round of budget cuts. The cuts are needed, his advisers say, to hold the 1982 deficit to Mr. Reagan's goal of $42.5 billion. Commerce Secretary Malcolm Baldrige said, however, that economic conditions might force the deficit as high as $50 billion in the fiscal year 1982, which begins Oct. 1. Mr. Baldrige, the first high Administration official to publicly question the figure set by Mr. Reagan, said that the stability of the financial markets could be restored if the deficit were held to $50 billion. Coming that close to $42.5 billion, rather than allowing the deficit to soar as high as the $80 billion some have forecast, would convince Wall Street that the economic recovery program is working, Mr. Baldrige said.

A broad range of Wall Street economists said yesterday that President Reagan's cuts in military spending did not even qualify as a ''gesture'' toward easing the concerns of the financial markets that his economic program will be inflationary. In interviews, the economists asserted that, if military spending were not cut more, the President would have to seek further huge reductions in social programs, some form of tax increase or a reduction in high interest rates. ''It might be easier politically to rescind part of the tax cuts,'' said Audrey Freedman, labor economist at the Conference Board, a business-sponsored economic research organization, ''than go through the additional cutbacks in defense and social program spending that will be required if the President is to reach his deficit target; something is going to have to give.'' 'A Complete Reassessment' ''What we are really talking about,'' said Leonard Santow, senior vice president and economist for the J. Henry Schroeder Bank and Trust Company, ''is a complete reassessment of the entire Reagan program and the premises upon which it was based.''

Before the air traffic controllers' strike, the Greater Pittsburgh International Airport handled as many as 110 flights an hour. Today the airport handled 77 flights from 9 to 10 A.M.; it was the busiest hour of air traffic since the strike began six weeks ago. Pittsburgh's airport, the 12th busiest in the nation, has been a particular victim of the controllers' strike, suffering heavier declines in service than any other. But even there, where the number of controllers is down by more than a third, traffic is picking up again. ''The parking lots aren't full yet,'' said David L. Donahoe, the airport's director of aviation, ''but the business travelers are coming back.''

Short-term interest rates fell sharply yesterday as the Federal Reserve continued to increase the supply of bank reserves. At the weekly Treasury bill auction, three-month and six-month issues dropped more than a percentage point from the previous auction on Sept. 4, to a new average of 14.412 percent and 14.657 percent, respectively. ''The Fed h as been slowly putting more and more reserves into the banking syste m, which is bringing down short-term rates,'' one government se curities analayst said. The additional reserves make more money av ailable to banks for loans, thus easing the pressure on interest rate s. Fed Buys Securities The Fed yesterday purchased securities for foreign accounts, thus pumping money into the market, and this resulted in higher prices and lower interest rates for short-term and long-term issues, despite a move to lower prices in morning trading.

Peter F. Cohalan, the Suffolk County Executive, yesterday proposed a 1982 county budget that would require the laying off of 600 county employees, a reduction in county services and a property-tax increase. Describing the budget as ''draconian,'' Mr. Cohalan said that despite the layoffs and sharp cuts in services, the tax increase was necessary to pay for increased expenditures required under state and federally mandated programs, such as Medicaid assistance and publicwelfare programs. The county property-tax bill for the average Suffolk County home , fully assessed at $40,000, would rise by $21. 60 next year, according to the deputy county executive for finance, W illiam Brotherton. The cuts proposed in the county work force would involve 1,200 positions, but 600 of those have already left through attrition or retirement.

Moody's Investors Service, one of the natio n's principal securitiesrating agencies, yesterday gave New York City 's short-term notes the firmest endorsement they have enjoyed since t he start of the fiscal crisis in the mid-1970's. Moody's assigned the notes a MIG-2 rating, the second highest grade possible - behind MIG-1 - and an evaluation assigned to securities of ''high quality'' and ''ample'' margins of protection. MIG stands for Moody's Investment Grade. As New York prepared for a $200 million note sale tomorrow, Moody's asserted that the city's cash position was strong enough to give it what the rating agency called ''a well-structured operation.''