Washington — Mark Twain, besides his ear for colloquial metaphor, had the talent of losing astounding sums of money on others' inventions. After a few warm-up debacles in earlier decades, he capped his investing career in the 1890s by losing $190,000 on a mechanical typesetter.
Through it all he retained a fondness for tinkering with his own frivolous consumer products (a self-pasting scrapbook, a game to help remember historical dates) and a fascination with Yankee ingenuity and its cultivation. In ''A Connecticut Yankee at King Arthur's Court,'' Twain wrote: ''A country without a patent office and good patent laws is just a crab and can't travel anyway but sideways and backways.''
At a time when almost every American industry is scrambling to innovate, the patent system should act as an encouragement for change. But some troubling statistics have many patent-holders worried. Over 50 percent of the patents challenged in court are struck down. In certain circuit courts of appeals, over 80 percent of challenged patents are ruled invalid.
For six years, Congress has considered creating a single patent court of appeals, to simplify patent adjudication. The idea is now closer to reality than it has ever been. Passed by House and Senate, it awaits clearance through a conference committee before becoming reality. But some fancy parliamentary footwork may delay the bill's passage.
At present, there are 12 federal appeals courts. The Court of Appeals Act of 1981 would create a 13th appellate court by merging the existing Court of Claims with the Court of Customs and Patent Appeals. Unlike its 12 brethren, the new court would have a specialized area of jurisdiction: It would hear appeals concerning patents, government contracts, trademarks, and international trade.
Claims against the government - which would have landed in the old Court of Claims - would be handled by another new forum, the US Claims Court.
For one thing, proponents of the move say, a 13th federal appeals court could help carry the growing burden of cases. Between 1962 and 1979 the number of appeals quadrupled, from 5,000 to 20,000.
Those who argue against the system say that right now the validity of a patent depends on geography, not law. Some appeals courts look kindly on patents. Others, such as for the Eighth Circuit, consider patents a mild form of monopoly, and strike down over 80 percent of the patents challenged in their jurisdiction.
But the main good would be increased uniformity in patent law - ''one of the most far-reaching reforms that could be made to strengthen the US patent system in such a way as to foster technological growth and industrial innovation,'' said Rep. Robert W. Kastenmeier (D) of Wisconsin, in introducing the measure in the House.
''We strongly support the creation of a new court of appeals,'' said patent commissioner Gerald Mossinghoff in a recent interview. ''What that will guarantee is that for the first time you'll have a single court telling the patent office what the standard of patentability is.''
The Reagan administration, carrying on a tradition of strong executive support for patents (Thomas Jefferson called patents ''a spring to invention beyond my conception''), has provided funds for increasing the number of patent examiners. But as Joseph Allen, director of Intellectual Property Owners, points out, ''As long as the courts can't agree, any administrative change is just dust in the wind.''
Most groups involved with patents support the change. ''I'm definitely in favor of it,'' says a Washington patent attorney. ''Most of the (patent lawyers) I've talked to are for it.''
But, like most things in life and all things in Congress, the bill has its critics. The American Bar Association is against it. Rep. F. James Sensenbrenner Jr. (R) of Wisconsin thinks it would open the door to a flood of unnecessary, specialized appeals courts. Since only 191 of the 20,000 appeals cases filed in 1979 dealt with patents, he points out, the new patent court wouldn't spread the workload much. And he believes the problem of 12 courts with 12 standards of patentability shouldn't be solved this way.
''That's a criticism (the problem of contradictory decisions by separate appeals courts) that has been leveled against our whole federal appeals process, '' an aide to Mr. Sensenbrenner says. ''It should be addressed in a national way.''
The House and Senate need to reconcile differences in their bills before the court can be established. And one difference is gumming up the works. Sen. Bob Dole (R) of Kansas attached an amendment dealing with grain elevators to the Senate version. The House, angered, may drag its heels on calling the final conference.