SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Kelly James Patrick (Last) (First) (Middle) C/O CABOT CORPORATION TWO SEAPORT LANE, SUITE 1300 (Street) BOSTON MA 02210 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol CABOT CORP [ CBT ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) Controller
	3. Date of Earliest Transaction (Month/Day/Year) 08/06/2007
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	08/06/2007		A		6,000	A	$13.8	25,448(1)	D
Common Stock								6,549.0298(2)	I	Through the Trustee of the Corporation's Retirement Savings Plan.

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents acquisition of shares of restricted stock awarded under Cabot's 2007 long-term incentive program. Under the terms of the award, the per share purchase price is 30% of the closing market price of Cabot common stock on May 10, 2007 ($13.80), the date the award was approved by the Compensation Committee of Cabot's Board of Directors. Mr. Kelly was required to pay the purchase price for the shares by August 6, 2007. Mr. Kelly paid the purchase price on August 6, 2007 with a loan from Cabot.

2. Prior to July 20, 2007, retirement plan contributions made by the Company under the Employee Stock Ownership Plan portion of Cabot's Retirement Savings Plan were made with shares of Series B ESOP Convertible Preferred Stock. Each share of this preferred stock was convertible into 146.3782 shares of Cabot's common stock. On July 20, 2007, all of the preferred stock held by the Trustee of the Retirement Savings Plan was converted to common stock. The amount reported here includes amounts that previously would have been reported under Table II as Series B ESOP Convertible Preferred Stock as well as retirement plan contributions made by the Company under the 401(k) portion of the Retirement Savings Plan.

Remarks:

	Michaela Allbee, pursuant to a power of attorney from James Kelly	08/08/2007
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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