During the 1947-48 season the Boston Symphony Orchestra lost $101,000. Last year it lost $139,000. And this year expectations are that it will lose $180,000. Yet Symphony Hall is sold out almost completely for every one of its four weekly concerts.

But with every seat taken for every concert the receipts are not sufficient to pay even the musician's salaries. Administrative costs, transportation expenses, and the operation of Symphony Hall must be paid for after the musicians are taken care of. Normally orchestras rely on radio broadcasts and record royalties to make up the deficit.

Two years ago, however, the National Broadcasting Company stopped broadcasting the BSO's Tuesday evening concerts. Last year the Sunday afternoon Pops concerts stopped going on the air. This accounts for part of the mounting yearly deficit.

The reasons for this loss of broadcasting time by the Boston Symphony were not made public. But it is known that the Hooper rating of a symphony orchestra broadcast is low; the most popular orchestra on the air, The New York Philharmonic, has only five million listeners as compared to the twenty million for Jack Benny or Bob Hope.

In the second place an hour symphony concert admits at most only three spots for commercials, as opposed to the limitless advertising time on a half hour show such as the Hit Parade. Third, the radio station, and hence the sponsor, has to pay more to hire a large orchestra than it does to employ a smaller group.

At the same time that the Boston Symphony went off the air the RCA Victor Company, for which the orchestra records, got caught promoting the wrong record speed. This blunder was felt by the Orchestra last year, when it cut almost no records. Until all companies settle down at 33 revolutions per minute, the Orchestra will be making even less records.

Finally, most cultural, non-profit institutions exist mainly on earnings derived from investments. The Boston Symphony, however, has a capital investment of only $428,000, the earnings of which are negligible.

Despite all this the Orchestra is better off than almost any in the country because of its traditionally loyal followers. The Friends of the Boston Symphony last year gave it $18,000. Another proof of the strong bond between the Proper Bostonian and his Orchestra is the fact that $80,000 came from legacies. The remaining deficit must be made up by a portion of the Serge Koussevitzky 25th Anniversary Fund.

The trustees hope that before this fund runs out the 20 percent amusement tax will be repealed. When this happns the cost of tickets will remain the same but the orchestra will benefit. Meanwhile the trustees pride themselves on never having to tamper with a program with an eye to the gate. Symphony Hall is always full. And at a time when orchestras such as the Detroit Symphony have folded, the Boston Symphony carries on, and manages to present three expensive summer features on top of its heavy winter schedule.