WE WOULDN'T be surprised to hear that some senators are using less than printable language to describe one provision of a supplemental appropriations bill passed by the House last week. The provision imposes on senators the same kind of cap that is imposed on House members, limiting the amount of outside income they can earn from giving speeches.

House members feel strongly about this because they took the political heat last year and voted themselves a straightforward pay increase to $69,800, while keeping the limit on outside earnings to some $20,000. The Senate, on the other hand, kept its members' salary at $60,662, but reaffirmed its 1981 vote removing all limits from outside earnings. In 1982, senators earned a total of $2.4 million i honoraria and the like, and five senators actually made more money, even after charitable contributions, from outside organizations than they did from their senatorial salaries. (Two columnists on today's op-ed page give their views on this subject.)

As you might expect, a lot of this outside money comes from organizations with very strong interests in certain legislation. No one can say that explicit vote-buying has taken place. But Reps. Silvio Conte (R-Mass.) and Vic Fazio (D-Calif.) are not being frivolous when they complain that House members, "buffeted around on the pay increase," are also "getting tarred with the same brush" on honoraria. The ordinary voter, hearing of such shenanigans, is not likely to make fine distinctions between one house and the other. In fact, over the long haul of American history, there have been very few times when the House and the Senate have had different pay arrangements.

Of course, there's not a snowball's chance in the Senate steam room that the House's cap on Senate honoraria will become law: the Senate will never allow it. Speaker O'Neill has already made it clear that he's not sure that the House should interfere in what senators will regard as the Senate's business, and other House members may fear Senate retaliation against their own pay increase. What should happen here is simple. The Senate should, on its own, vote itself a fair pay increase. And it should impose the cap on outside earnings of the sort the House has now and the Senate had before 1981. That's the straightforward way to see that the public business is done by men and women paid by the public--not by private parties with their own particular interests.