1
                                                                   EXHIBIT 10.80


                     [FERROFLUIDICS CORPORATION LETTERHEAD]


MEMO OF UNDERSTANDING



DATE:     August 2, 1999


TO:       Mr. David C. Lewandoski
          31 Shipley Drive
          Hollis, New Hampshire 03049


This memo confirms our discussions leading to a change in your employment
agreement effective August 2, 1999, as outlined below:

     *    Your title remains Controller, and your employment with the
          corporation continues to be at will.

     *    If you should be severed from the company by a corporate change in
          control, you will receive a lump-sum payment of six months salary.

     *    All other benefit entitlements, with the exception of the severance
          payment described above, will be the same as for any other employee,
          and all outstanding option and stock arrangements remain unchanged.

Please acknowledge your acceptance of these terms by signing below and returning
one copy of this letter to Human Resources.




/s/ Paul F. Avery, Jr.
- -------------------------
Paul F. Avery, Jr.
President & CEO



ACCEPTED:


/s/ David C. Lewandoski
- -------------------------
David C. Lewandoski