EXHIBIT 10.21



Meridian Bank       Meridian Bank has merged          Promissory Note (Business)
                    with CoreStates Bank, N.A.
$ 560,000.00                                          March 26, 1998
- ------------------                                    ------------------------

FOR VALUE RECEIVED, Undersigned,  intending to be legally bound, promises to pay
to the order of Meridian  Bank  ("Bank"),  a  Pennsylvania  banking  corporation
having an office at 35 North Sixth Street, Reading,  Pennsylvania, the principal
sum of Five Hundred Sixty Thousand and 00/100 Dollars payable as provided below,
with  interest  accruing at the rate of the Bank's  National  Commercial  Rate +
 .50% per annum  until  paid.  Interest  shall be  computed on the basis of the
actual number of day in the calendar year divided by 360.

     If the  interest  rate set  forth  above is  referenced  to  either  Bank's
National Commercial Rate, Local Commercial Rate or Agricultural Commercial Rate,
Undersigned  acknowledges and agrees that (i) such referenced rate is a floating
annual  rate of  interest  that is  designated  from time to time by Bank as the
"National Commercial Rate," "Local Commercial Rate" or "Agricultural  Commercial
Rate," as the case may be, and is used by Bank as a reference  rate with respect
to  different  interest  rates  charged to  borrower;  (ii) the rate of interest
payable hereunder shall change  simultaneously and automatically upon any change
in such  referenced  rate; and (iii) such  referenced rate may not be the lowest
rate at which Bank makes loans to other borrowers.

REPAYMENT TERMS

     1.  (Single Principal Payment Loan) Interest on the unpaid principal is due
         and  payable  monthly  beginning  April 30,  1998 . The full sum of the
         unpaid principal and interest is due and payable on September 3, 1998 .

     2.  (Discounted  Time  Note)  The  full sum is due and  payable  in days on
         _______________.

     3.  (Demand  Loan)  Interest  on the unpaid  principal  is due and  payable
         _______________  beginning  __________.  The  full  sum of  the  unpaid
         principal and interest is due and payable on demand.

     4.  (Credit  Availability)  Interest  on the  unpaid  principal  is due and
         payable _______________ beginning _______________.  The full sum of the
         unpaid  principal  and interest is due and payable on  _______________.
         Bank may make advances and readvances to Undersigned as Undersigned may
         request in accordance with, and subject to, the provisions of this Note
         and  any  other  agreements,   documents  or  instruments  executed  in
         connection   herewith  and  related   thereto,   and  any   extensions,
         modifications or renewals thereof and substitutions therefor,  provided
         however, that the credit so extended shall not exceed the principal sum
         stated above and such commitment may terminate at Bank's option.

     5.  (Installment  Loan)  Principal  and  interest  are due and  payable  in
         __________ consecutive _______________ installments of $_______________
         each,  beginning  _______________.  One final  payment of any remaining
         unpaid principal and interest is due and payable on _______________.

     6.  (Principal  Plus  Interest  Loan)  Principal  is  due  and  payable  in
         __________ consecutive _______________ installments of $_______________
         each,  beginning  _______________.  Interest on the unpaid principal is
         due and payable _______________  beginning  _______________.  One final
         payment of  $_______________  together with any remaining principal and
         accrued interest is due and payable on _______________.

         Undersigned   authorizes   Bank   to   charge   its   deposit   account
#_______________  for  the  payment  of  principal  and/or  interest  hereunder.
Undersigned  shall owe a late  payment  charge equal to the greater of 5% of the
unpaid amount of any scheduled payment or $15.00, whenever payment of the entire
amount due on any date is not received by Bank on such date.

LIABILITIES

     The term  "Liabilities"  means the principal and interest evidenced by this
note and all other  liabilities  of Undersigned  to Bank,  whether  hereunder or
otherwise,  whether now existing or hereafter  incurred,  matured or  unmatured,
direct or contingent,  joint or several, whether created directly or acquired by
assignment or otherwise,  including all past and future  advances or readvances,
and  any  extensions,   modifications  or  renewals  thereof  and  substitutions
therefor;  all amounts advanced by Bank hereunder on behalf of Undersigned;  all
late  charges,  penalties,  fees and  other  such  sums due  under  this Note or
otherwise;   all  liabilities   (including   Professional  Fees  and  Costs,  as
hereinafter  defined)  incurred by Bank arising from or related to any hazardous
materials or dangerous  environmental  conditions at any real property  owned or
occupied  by  Undersigned;  and all of Bank's  costs and  expenses  incurred  in
connection  with the  enforcement  and collection of the foregoing  liabilities,
whether or not suit is  instituted,  and whether or not bankruptcy or insolvency
proceedings have been instituted by or against Undersigned,  including,  without
limitation,  reasonable  fees and costs of attorneys,  appraisers,  accountants,
consultants and other professionals ("Professional Fees and Costs"). All amounts
advanced by Bank hereunder on behalf of Undersigned  and all other fees,  costs,
and expenses  incurred by Bank and included in the Liabilities  shall be due and
payable upon demand,  with interest at an annual rate which shall be two percent
(2%) above the rate of interest  otherwise payable  hereunder,  from the date of
payment by Bank until paid in full.

COLLATERAL

     All  Collateral  (as  defined) is security  for the  Liabilities.  The term
"Collateral"  includes all tangible and intangible property (i) described in any
mortgage  or other  security  document  separately  executed by  Undersigned  in
connection with the  Liabilities in favor of Bank  ("Security  Documents") , and
(ii) in which  Undersigned  has granted a security  interest to Bank pursuant to
this Note. Undersigned grants Bank a security interest in all monies, securities
and other property of Undersigned and the proceeds thereof,  now or hereafter in
the  possession or custody of, or in transit to, Bank, or any of its  affiliates
or  subsidiaries,  for  safekeeping,  collection,  pledge or any  other  purpose
including,  without  limitation,  all deposits  (whether general or special) and
credits now or hereafter  maintained  by  Undersigned  with Bank,  or any of its
affiliates or  subsidiaries,  and in any claims of Undersigned  against Bank, or
any of its affiliates or  subsidiaries,  and Bank may, at its option and without
notice, set off toward the payment of any Liabilities, in such order as Bank may
determine,  the balance of each such account with,  and each claim against Bank,
or any of its affiliates or subsidiaries.  Bank is deemed to have exercised such
right of set off and to have made a charge against any such account  immediately
upon the  occurrence  of a Default  (as  hereinafter  defined)  even though such
charge is made or entered on the books  subsequently  by Bank.  Bank has, but is
not limited to, the right at any time and from time to time,  without notice to:
(a)  pledge,  assign or  transfer  this Note or the  Collateral  or any  portion
thereof;  (b) transfer  into its own name or that of its nominee all or any part
of the  Collateral;  (c)  exercise  voting  rights on any  Collateral;  (d) take
control of the proceeds of any Collateral.

DEFAULT

     The  occurrence  of any one or more of the  following  shall  constitute  a
Default by the Undersigned:  (a) non-payment of any of the  Liabilities,  or any
portion  thereof,  when  and in the  manner  due,  whether  by  acceleration  or
otherwise;  (b)  failure by  Undersigned  to observe  or perform  any  covenant,
agreement,  condition or term of any  agreement,  document or Security  Document
executed and delivered by Undersigned in connection with any of the Liabilities;
(c) breach by any of  Undersigned  of any  obligation  or duty to Bank;  (d) any
representation  or  warranty  in any  financial  or other  statement,  schedule,
certificate or other  document  delivered to Bank by or on behalf of Undersigned
shall prove to be false, misleading or incomplete in any material respect; (e) a
material adverse change occurs in the financial  condition of Undersigned  which
is  unacceptable to Bank in its sole discretion from the condition most recently
disclosed to Bank in any manner;  (f) Undersigned dies,  dissolves,  liquidates,
merges,   reorganizes,   changes  its  name,  sells  or  otherwise  disposes  of
substantially all of its assets or ceases to conduct operations,  or prepares or
attempts to do any of the foregoing;  (g) a trustee or receiver is appointed for
Undersigned or for a substantial part of its property,  or Undersigned commences
any bankruptcy or other similar  proceedings  under any insolvency law, state or
federal,  or any such proceeding is commenced against Undersigned or Undersigned
becomes  insolvent,  or generally fails to pay or is generally unable to pay its
debts,  or makes an assignment for the benefit of creditors or admits in writing
its insolvency or inability or failure to pay its debts generally as they become
due, or fails within 30 days to pay or bond or otherwise  discharge any judgment
which is  unstayed  pending  appeal;  (h)  Undersigned  expresses  an  intent to
terminate,  revoke,  or  challenge  responsibility  for any  Liabilities  or any
material term of any document  executed in connection  with the  Liabilities  is
found or declared to be invalid by a court of  competent  jurisdiction;  (i) any
property of Undersigned becomes the subject of any attachment, garnishment, levy
or lien  (unless  expressly  permitted  in  writing  signed  by  Bank);  (j) any
substantial  part of the  property of  Undersigned  is taken or condemned by any
governmental  authority;  (k)  Undersigned  assigns or otherwise  transfers,  or
attempts to assign or transfer,  any of its right,  title and interest in any of
the Collateral  without the prior written consent of Bank; (l) Undersigned fails
to furnish financial or other information as Bank may reasonably request; (m) if
there is any change in Undersigned's officers,  principal owners or partners, as
the case may be, which is unacceptable to Bank in its sole discretion; (n) Bank,
in the reasonable and good faith exercise of its sole  discretion,  deems itself
insecure for any reason whatsoever;  or (o) Undersigned defaults under any other
agreement or instrument  applicable to it representing a material obligation and
such default is not remedied  within the grace period provided in such agreement
or instrument or waived.

REMEDIES

     Upon the occurrence of a Default (a) Bank shall have no further obligations
to advance funds to Undersigned  hereunder;  (b) all  Liabilities  shall, at the
option of Bank, be  immediately  due and payable;  and (c) Bank may exercise its
right of set-off as set forth  herein,  any and all  remedies  available to Bank
under  this  Note  and the  Security  Documents,  and all  rights  and  remedies
available to it under any applicable law,  including,  without  limitation,  the
rights and  remedies  of a secured  party  under the  Uniform  Commercial  Code.
Undersigned hereby waives notice of presentment for payment, demand,  nonpayment
or  dishonor,  protest,  acceleration  and all  further  notice  of any  kind in
connection with the delivery,  acceptance,  default or enforcement of this Note,
and hereby  waives  all notice or right of  approval  of  extensions,  renewals,
modifications or forebearances which may be allowed.

         Upon the  occurrence of any Default and the  continuance  thereof,  and
upon prior written notice to  Undersigned  by Bank,  interest shall accrue at an
annual rate which shall be two percent (2%) above the rate of interest otherwise
payable  hereunder.  At the option of Bank,  interest which is not paid when due
shall be added to principal.  If any of the  Liabilities or any portion  thereof
owing to Bank is not paid in full when due,  Bank may, at its option and without
notice,  withdraw from any account of  Undersigned  with Bank an amount equal to
such  overdue  amount and to apply  such  amount to the  payment of the  overdue
Liabilities.

         All rights or  remedies  of Bank set forth or  otherwise  existing  are
cumulative.  Neither  any delay or failure  by Bank,  in  exercising  any of its
options,  powers or rights herein,  nor any partial or single  exercise  thereof
shall  constitute  a waiver of the right to exercise the same or any other right
at any  other  time or from time to time  thereafter.  Bank is not  required  to
resort to any particular security or persons to enforce payment, and Bank is not
subject to any marshalling  requirements of equities among Undersigned,  if more
than one, and among it or them.

CONFESSION OF JUDGMENT

         UNDERSIGNED  HEREBY  IRREVOCABLY  AUTHORIZES  AND EMPOWERS BANK, BY ANY
AUTHORIZED  OFFICER,   EMPLOYEE  OR  AGENT,  OR  BY  ITS  ATTORNEY,  OR  BY  THE
PROTHONOTARY OR CLERK OF ANY COURT OF RECORD IN THE COMMONWEALTH OF PENNSYLVANIA
OR ELSEWHERE WHERE PERMITTED BY LAW, UPON THE OCCURRENCE OF A DEFAULT, TO APPEAR
FOR  AND  CONFESS  JUDGMENT  AGAINST   UNDERSIGNED  IN  FAVOR  OF  BANK  IN  ANY
JURISDICTION  IN WHICH  UNDERSIGNED  OR ANY OF ITS  PROPERTY  IS LOCATED FOR THE
AMOUNT  OF ANY OR ALL OF THE  LIABILITIES,  TOGETHER  WITH THE COSTS OF SUIT AND
WITH ACTUAL  COLLECTION  COSTS,  INCLUDING  REASONABLE  ATTORNEYS' FEES, WITH OR
WITHOUT DECLARATION,  WITH RELEASE OF ALL ERRORS,  WITHOUT STAY OF EXECUTION AND
THE  RIGHT TO ISSUE  EXECUTION  FORTHWITH,  AND FOR DOING SO THIS NOTE OR A COPY
VERIFIED BY AFFIDAVIT SHALL BE A SUFFICIENT  WARRANT.  UNDERSIGNED HEREBY WAIVES
AND RELEASES ALL RELIEF FROM ANY AND ALL APPRAISEMENT,  STAY OR EXEMPTION LAW OF
ANY STATE NOW IN FORCE OR HEREINAFTER ENACTED.

         UNDERSIGNED  ACKNOWLEDGES  THAT  BY  AGREEING  THAT  BANK  MAY  CONFESS
JUDGMENT HEREUNDER, IT WAIVES THE RIGHT TO NOTICE IN A PRIOR JUDICIAL PROCEEDING
TO DETERMINE ITS RIGHTS AND LIABILITIES,  AND UNDERSIGNED  FURTHER  ACKNOWLEDGES
THAT BANK MAY OBTAIN A JUDGMENT AGAINST UNDERSIGNED WITHOUT  UNDERSIGNED'S PRIOR
KNOWLEDGE OR CONSENT AND WITHOUT THE OPPORTUNITY TO RAISE ANY DEFENSE,  SET OFF,
COUNTERCLAIM  OR OTHER CLAIM  UNDERSIGNED  MAY HAVE, AND  UNDERSIGNED  EXPRESSLY
WAIVES SUCH RIGHTS AS AN EXPLICIT AND MATERIAL  PART OF THE  CONSIDERATION.  THE
FOREGOING POWER TO CONFESS JUDGMENT MAY BE EXERCISED AGAINST  UNDERSIGNED AT ONE
TIME OR AT  DIFFERENT  TIMES AS BANK  ELECTS  UNTIL  THE  LIABILITIES  ARE FULLY
DISCHARGED.

MISCELLANEOUS

         The  invalidity  of any  portion  of this  Note  shall not  affect  the
remaining  portions,  or  any  portion  thereof,  and in the  case  of any  such
invalidity,  this  Note  shall  be  construed  as if such  portion  had not been
inserted.  Undersigned,  if more than one, are jointly and severally liable, and
the term  "Undersigned"  whenever used means each of the parties  executing this
Note. All of the terms and provisions of this Note inure to and are binding upon
the heirs, executors, administrators,  successors,  representatives,  receivers,
trustees and assigns of Bank and Undersigned.

         Undersigned  irrevocably  waives  the right to  interpose  any  defense
(other than payment),  set-off or  counterclaim  of any nature or description in
any and all disputes  between  Undersigned and Bank,  whether under this Note or
under any other agreement heretofore or hereafter executed.

         Undersigned   irrevocably   agrees  and   consents  to  the   exclusive
jurisdiction of the Courts of Common Pleas for any county in Pennsylvania  where
Bank has an office  and/or  the United  States  District  Court for the  Eastern
District of Pennsylvania in any and all disputes, actions or proceedings between
Undersigned and Bank,  whether arising hereunder or under any other agreement or
undertaking  and  irrevocably  agrees to service of process by  certified  mail,
return receipt requested, to Undersigned at the address listed on the records of
Bank and,  if more than one  Undersigned,  that  service  upon any of them shall
constitute  service upon all of them, each, hereby appointing the other(s) their
attorney-in-fact for the purpose of service. However, Bank is not precluded from
bringing an action against any of Undersigned in any  jurisdiction in the United
States or elsewhere in which  Undersigned,  or any of their property is located.
Undersigned  further  agrees  not to make any  objection  in any such  action or
proceeding that the venue is improper or the forum is inconvenient.

         All  terms,  obligations  and  provisions  hereof are  governed  by and
construed  in  accordance  with  the  internal  laws  of  the   Commonwealth  of
Pennsylvania, without reference to conflict of laws principles.

         All  notices,  comments and other  communications  required by or given
under  this Note  shall be in  writing  and  shall be given by  either  (i) hand
delivery,  (ii) first class mail (postage  prepaid),  (iii)  reliable  overnight
commercial  courier  (charges  prepaid),  or (iv)  telecopy  or  other  means of
electronic  transmission,  if confirmed  promptly by any of methods specified in
clauses (i), (ii),  and (iii) of this sentence and shall be  sufficient,  in the
case of Undersigned, if sent to the attention of its proprietor, general partner
or any executive officer at the address on the records of Bank, and, in the case
of Bank, if sent to the address and attention of the loan officer  servicing the
account of Undersigned.

         IN WITNESS WHEREOF, Undersigned has executed this Note the day and year
first above written.

Meridian Bank has merged
with CoreStates Bank, N.A.

BORROWER (if individuals, partnership, etc.)   BORROWER (if corporation)

                                              Rhetech, Inc.
- ----------------------------------            ----------------------------------
Business Name, if any                         Corporate Name


                                              By: /s/Charles D. Brown
- ----------------------------------            ----------------------------------
                                                     Title: Charles D. Brown,
                                                            President/CEO

                                              By: /s/Joseph A. Yurgosky
- ----------------------------------            ----------------------------------
                                                     Title: Joseph A. Yurgosky,
                                                            Secretary

                                              Attest:
- ----------------------------------            ----------------------------------
                                                     Title:


                                               (Corporate Seal)
- ----------------------------------            



                                              Witness: /s/Cheryl Davis
- ----------------------------------            ----------------------------------






                            CORPORATE ACKNOWLEDGMENT

STATE OF PENNSYLVANIA               :
                                    :       ss.
COUNTY OF LEHIGH                    :

     On this the 26th day of MARCH,  1998 before me, a Notary  Public in and for
said County and State,  personally  appeared  CHARLES D. BROWN,  known to me (or
satisfactorily  proven) to be the PRESIDENT and CHIEF EXECUTIVE  OFFICER (C.E.O)
of RHETECH,  INC., a Delaware  Corporation,  and that he as such officer,  being
authorized to do so, executed the foregoing  instrument for the purposes therein
contained  by signing the name of the  Corporation  by himself as such  officer.
WITNESS my hand and notarial seal the day and year aforesaid.

 /s/Robin L. Cunconan-Lahr                 My Commission Expires: March 12, 2001
- ------------------------------------
Notary Public



NOTARIAL SEAL



                            CORPORATE ACKNOWLEDGMENT

STATE OF PENNSYLVANIA               :
                                    :       ss.
COUNTY OF LEHIGH                    :

     On this the 26th day of MARCH,  1998 before me, a Notary  Public in and for
said County and State,  personally appeared JOSEPH A. YURGOSKY,  known to me (or
satisfactorily  proven)  to be  the  Secretary  of  RHETECH,  INC.,  a  Delaware
Corporation,  and that he as such officer,  being  authorized to do so, executed
the foregoing  instrument for the purposes therein contained by signing the name
of the Corporation by himself as such officer.
WITNESS my hand and notarial seal the day and year aforesaid.

 /s/Robin L. Cunconan-Lahr                 My Commission Expires: March 12, 2001
- ------------------------------------
Notary Public



NOTARIAL SEAL