1 EXHIBIT 24(a) POWER OF ATTORNEY We, the undersigned directors and officers of Cabot Corporation, hereby severally constitute and appoint Robert Rothberg and Charles D. Gerlinger, and each of them, our true and lawful attorneys with full power to (i) sign for us and in our names in the capacities indicated below Annual Reports on Form 10-K pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 of Cabot Corporation for the fiscal year ended September 30, 1994, and subsequent years, and any and all amendments thereto, hereby ratifying and confirming our signatures as they may be signed by our said attorneys, or either of them, to said Reports and to any and all amendments to said Reports; and (ii) to file such Reports and amendments with the Securities and Exchange Commission on behalf of Cabot Corporation. WITNESS our hands and common seal on the date set forth below. Signature Title Date - --------- ----- ---- /S/ Samuel W. Bodman Director, Chairman and November 11, 1994 - ------------------------ President (Chief Executive Samuel W. Bodman Officer) /S/ John G.L. Cabot Director, Vice Chairman November 11, 1994 - ------------------------ and Chief Financial Officer John G.L. Cabot /S/ William R. Thompson Vice President and November 11, 1994 - ------------------------ Controller William R. Thompson (Principal Accounting Officer) /S/ Damaris Ames Director November 11, 1994 - ------------------------ Damaris Ames /S/ Jane C. Bradley Director November 11, 1994 - ------------------------ Jane C. Bradley /S/ Kennett F. Burnes Director November 11, 1994 - ------------------------ Kennett F. Burnes 2 Signature Title Date - --------- ----- ---- /S/ Robert A. Charpie Director November 11, 1994 - --------------------------- Robert A. Charpie /S/ John D. Curtin, Jr. Director November 11, 1994 - --------------------------- John D. Curtin, Jr. /S/ Robert P. Henderson Director November 11, 1994 - --------------------------- Robert P. Henderson /S/ Arnold S. Hiatt Director November 11, 1994 - --------------------------- Arnold S. Hiatt - --------------------------- Director November 11, 1994 Gerrit Jeelof /S/ John H. McArthur Director November 11, 1994 - --------------------------- John H. McArthur /S/ John F. O'Brien Director November 11, 1994 - --------------------------- John F. O'Brien /S/ David V. Ragone Director November 11, 1994 - --------------------------- David V. Ragone /S/ Charles P. Siess, Jr. Director November 11, 1994 - --------------------------- Charles P. Siess, Jr. /S/ Morris Tanenbaum Director November 11, 1994 - --------------------------- Morris Tanenbaum /S/ Lydia W. Thomas Director November 11, 1994 - --------------------------- Lydia W. Thomas - 2 -