Exhibit 5








December 22, 1998

Eastern Enterprises
9 Riverside Road
Weston, MA 02493

You have asked for my opinion concerning the legality of 28,415 shares of Common
Stock,  with  a par  value  of  $1.00  per  share  (the  "Shares"),  of  Eastern
Enterprises  (the  "Association")  issuable upon the exercise of options granted
under the Essex Gas  Company  1994 Stock  Option  Plan (the  "Plan")  and 28,415
common stock purchase  rights (the "Rights")  attached to the Shares pursuant to
the provisions of a Common Stock Rights  Agreement  between the  Association and
BankBoston,  N.A.,  dated as of  February  22,  1990,  as amended  (the  "Rights
Agreement").

As Senior Vice President,  General Counsel and Secretary of the  Association,  I
have acted as counsel for the  Association in connection with the preparation of
the  Registration  Statement  on Form S-8 (the  "Registration  Statement")  with
respect to the Plan,  which is being  filed  with the  Securities  and  Exchange
Commission under the Securities Act of 1933  contemporaneously  herewith,  and I
have examined:

(a)      the Declaration of Trust of the Association dated July 18, 1929, as
         amended;

(b)      the By-laws of the Association as from time to time in effect;

(c)      a copy of the Registration Statement;

(d)                   the minutes of meetings  to date of the  shareholders  and
                      Board of Trustees of the Association and the  shareholders
                      and Board of Directors of Essex Gas Company;










Eastern Enterprises
December 22, 1998
Page 2


(e)      the Rights Agreement; and

(f) such other  documents  and records as I deem  necessary for purposes of this
opinion.

I have  assumed  that the Shares  proposed  to be issued  upon the  exercise  of
options under the Plan will be issued only upon payment  therefor as provided in
the Plan and that the price  for such  shares  will be not less  than  $1.00 per
share. I have also assumed that the issuance of any Shares  pursuant to the Plan
will not result in the issuance by the  Association  of more than its authorized
shares of the Association's  common stock. In addition,  I have assumed that the
Rights will be issued in accordance with the provisions of the Rights Agreement.

Based upon the foregoing, I am of the opinion that:

1.   The  Association  is  duly  organized  and  existing  as an  unincorporated
     voluntary  association in conformity  with the laws of The  Commonwealth of
     Massachusetts.

2.   The  Shares,  when  issued and paid for as  provided  in the Plan,  will be
     validly issued and will be fully paid and nonassessable except as set forth
     below in this opinion.

3.   The Rights,  when issued in accordance with the Rights  Agreement,  will be
     validly issued and will constitute binding obligations of the Association.

The  Association  is a voluntary  association  of the type  commonly  known as a
"Massachusetts  business  trust."  Pursuant to certain  decisions of the Supreme
Judicial Court of Massachusetts, shareholders of such a trust may, under certain
circumstances,  be held personally liable as partners for the obligations of the
trust.  Even if the  Association  were held to be a  partnership,  however,  the
possibility of its shareholders  incurring financial loss appears remote because
(a) the  Association's  Declaration of Trust  contains an express  disclaimer of
shareholder  liability for the  obligations of the Association and requires that
such notice be given in each agreement, obligation or instrument entered into or
executed by the










Eastern Enterprises
December 22, 1998
Page 3


Association,  (b) management of the Association has advised that the Association
is adequately  insured  against tort  liability,  (c) most of the  Association's
operations are conducted by incorporated  subsidiaries and (d) the Association's
Declaration of Trust provides for  indemnification out of the trust property for
any shareholder held personally  liable for the obligations of the Association.I
understand that this opinion is to be used in connection  with the  Registration
Statement.  I consent  to the filing of this  opinion  with and as a part of the
Registration Statement and to use of my name therein.


Very truly yours,


/s/ L. William Law, Jr.

L.       William Law, Jr.