EXHIBIT 10.39
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                                August ___, 2001


Yorkville Advisors Management, LLC
One World Trade Center, Suite 7705
New York, New York 10048
Attn:  Mark Angelo


     RE: PURCHASE OF CONVERTIBLE DEBENTURES

Dear Mr. Angelo:

     Celerity Systems,  Inc. (the "COMPANY")  desires to raise gross proceeds of
$1,500,000  from  the  sale  of  convertible   debentures.   Yorkville  Advisors
Management,  LLC (the  "Consultant") has agreed to assist the Company in raising
such proceeds on the terms and conditions set forth herein.

     1. CONSULTING AGREEMENT. On the date hereof, the Company and the Consultant
shall enter into a consulting  agreement  pursuant to which the Consultant  will
provide certain financial  consulting  services as more  particularly  described
therein.

     2. FEES. From the gross proceeds the Consultant  shall be paid (a) $470,000
for the services described in the Consulting Agreement, plus (b) a fee of 14% of
the gross  proceeds  (i.e.,  a total of $210,000 if gross proceeds of $1,500,000
are raised). In addition, the Company shall issue a warrant to the Consultant to
purchase up to  2,500,000  shares of the  Company's  common stock at an exercise
price of $0.10 per share.

     This  letter may be executed  in any number of  counterparts,  all of which
shall be deemed an original,  and all of which shall constitute one and the same
instrument.  This letter  shall be  accepted,  effective  and  binding,  for all
purposes,  when the parties shall have signed and  transmitted to each other, by
telecopier or otherwise,  copies of this letter.  In the event of any litigation
arising hereunder,  the prevailing party or parties shall be entitled to recover
its or their reasonable  attorneys' fees and court costs from the other party or
parties, including the costs of bringing such litigation and collecting upon any
judgments.  This letter  shall be binding upon and shall inure to the benefit of
the parties hereto and their respective heirs, executors, legal representatives,
trustees, successors and assigns.




     If the foregoing  correctly sets forth the terms of our  agreement,  please
sign this letter on the line  provided  below,  whereupon  it will  constitute a
binding agreement between us.

                                           Very truly yours,

                                           CELERITY SYSTEMS, INC.


                                           By:
                                               ---------------------------------

                                           Name:
                                                --------------------------------

                                           Title:
                                                 -------------------------------


Agreed and accepted on
August ___, 2001:


YORKVILLE ADVISORS MANAGEMENT, LLC


By:
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Name:
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Title:
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