BOSTON (AP) _ Cabot Corp., a chemicals and energy company, announced Wednesday it has cut 250 jobs, about 6 percent of its work force, as part of a broad plan to increase earnings and reduce costs by $30 million to $35 million.

The Boston-based company employs about 4,500 people, a spokeswoman said. Cabot is the world's largest producer of carbon black, which is used in printing and tire manufacturing.

Cabot also said it plans to make an initial public offering of about 15 percent of its microelectronic materials business and separate its liquefied natural gas unit from the rest of the corporation.

``We believe that the initiatives announced today will produce an increase in shareholder value and will allow us to refocus managerial resources on our core businesses,'' said Samuel Bodman, chairman and chief executive officer.

Cabot on Wednesday reported fiscal third-quarter earnings of $22.4 million, or 30 cents per share, down from $33.3 million, or 44 cents per share, the same quarter last year.

For the nine months ended June 30, Cabot earned $87.4 million, or $1.18 per share, down from $102.2 million, or $1.35 per share, in the year-ago period.

Revenues for the April-June quarter were up, nearly 13 percent, to $424.6 from $377.3. For the first three quarters, Cabot's revenue was fell $1.4 million to $1.27 billion in 1998.

Cabot has 45 manufacturing facilities in 23 countries.