UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  Schedule 13G

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 19)*

                             A. O. SMITH CORPORATION
                                (Name of Issuer)

                      Class A Common Stock, $5.00 par value
                         (Title of Class of Securities)

                                  831-865-10-0
                                 (CUSIP Number)


Check the following box if a fee is being paid with this  statement  /_/. (A fee
is not required only if the filing person:  (1) has a previous statement on file
reporting  beneficial  ownership  of more  than  five  percent  of the  class of
securities  described  in Item 1;  and (2) has  filed  no  amendment  subsequent
thereto reporting  beneficial  ownership of five percent or less of such class.)
(See Rule 13d-7.)

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).

                        (Continued on following page(s))




CUSIP No. 831-865-10-0                13G



1            NAME OF REPORTING PERSON
             S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

                 Smith Investment Company                  IRS ID #39-6043416
                 Lloyd B. Smith                            SS ####-##-####
                 Arthur O. Smith                           SS ####-##-####

2            CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                 Not Applicable

3            SEC USE ONLY

4            CITIZENSHIP OR PLACE OF ORGANIZATION

                 Smith Investment Company                  - Nevada
                 Lloyd B. Smith                            - United States
                 Arthur O. Smith                           - United States



NUMBER OF         5  SOLE VOTING POWER

SHARES                 Smith Investment Company            - 8,067,252

BENEFICIALLY      6  SHARED VOTING POWER

OWNED BY               -0-

EACH              7  SOLE DISPOSITIVE POWER

REPORTING              Smith Investment Company            - 8,067,252

PERSON            8  SHARED DISPOSITIVE POWER

WITH                   -0-

9            AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

                 Smith Investment Company                  - 8,067,252
                 Lloyd B. Smith                            - 0
                 Arthur O. Smith                           - 0

10           CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES 
             CERTAIN SHARES*

                 Lloyd B. Smith                            /x/
                 Arthur O. Smith                           /x/

11           PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

                 Smith Investment Company                  - 92.7%
                 Lloyd B. Smith                            - 0%
                 Arthur O. Smith                           - 0%

12           TYPE OF REPORTING PERSON*

                 Smith Investment Company                  - CO
                 Lloyd B. Smith                            - IN
                 Arthur O. Smith                           - IN

                     * SEE INSTRUCTIONS BEFORE FILLING OUT!



Item 1(a)        Name of Issuer:

                 A. O. Smith Corporation

Item 1(b)        Address of Issuer's Principal Executive Officers:

                 11270 West Park Place
                 Milwaukee, Wisconsin 53224

Item 2(a)        Name of Person Filing:

                 Smith Investment Company I.R.S.  I.D. No. 39-6043416
                 Lloyd B. Smith -- S.S. No. ###-##-####
                 Arthur O. Smith -- S.S. No. ###-##-####

Item 2(b)        Address of Principal Business Office or, if note, Residence:

                 Smith Investment Company
                 11270 West Park Place
                 Milwaukee, Wisconsin 53224

                 Lloyd B. Smith
                 11270 West Park Place
                 Milwaukee, Wisconsin 53224

                 Arthur O. Smith
                 11270 West Park Place
                 Milwaukee, Wisconsin 53224

Item 2(c)        Citizenship

                 Nevada -- Smith Investment Company
                 United States -- Lloyd B. Smith and Arthur O. Smith

Item 2(d)        Title of Class or Securities:

                 Class A Common Stock, $5.00 par value

Item 2(e)        CUSIP Number

                 831-865-10-0

Item 3           If this statement is filed pursuant to Rules 13d-1(b), or 
                 13d-2(b), check whether the person filing is a:

                 Not applicable



Item 4.          Ownership

                      As of December 31, 1998, Smith Investment Company owned
                 8,067,252 shares of A. O. Smith  Corporation  Class A Common
                 Stock or approximately 92.7% of the outstanding stock. Smith
                 Investment  Company  has sole  power to vote and  dispose of
                 such shares.

                      Mr.  Arthur O. Smith is a director of Smith  Investment
                 Company.  He retired as Chairman and Chief Executive Officer
                 of Smith  Investment  Company in January 1999.  During 1993,
                 Mr. Lloyd B. Smith retired as Vice  President and a director
                 of Smith Investment Company.

                      On   December   31,   1998,   Arthur  O.  Smith   owned
                 beneficially  235,590  shares,  and his wife owned of record
                 and  beneficially  6,970  shares of the  outstanding  common
                 stock of  Smith  Investment  Company  ("SICO")  and  399,560
                 shares  were held in various  trusts for the  benefit of the
                 wife and issue of Arthur O.  Smith.  On December  31,  1998,
                 Lloyd  B.  Smith  owned  beneficially  1,924  shares  of the
                 outstanding  common  stock of SICO and  624,086  shares were
                 held in various trusts for the benefit of the wife and issue
                 of Lloyd B. Smith. In addition,  Messrs. Smith were trustees
                 of  various  trusts for the  benefit  of persons  other than
                 themselves,  their  wives and issue,  which  trusts  held an
                 aggregate  of  1,003,520  shares of the common stock of SICO
                 outstanding on December 31, 1998. Messrs.  Smith have shared
                 investment and voting power on all trusts for which they are
                 co-trustees.  On all other  trusts  one or the other  shares
                 trust powers with at least one other  person.  The shares of
                 common stock of SICO held beneficially by Messrs.  Smith and
                 their wives,  together with shares held by Messrs.  Smith in
                 trust  for   others   comprised   68.5%  of  the   3,317,066
                 outstanding  shares of common  stock of SICO on December 31,
                 1998.  Messrs.  Smith  disclaim  that  any of the  foregoing
                 interests in the common stock of SICO constitute  beneficial
                 ownership  of any  Class  A  Common  Stock  of A.  O.  Smith
                 Corporation.

Item 5           Ownership of Five Percent or Less of a Class:

                 Not applicable

Item 6           Ownership of More than Five Percent on Behalf of Another 
                 Person:

                 Not applicable

Item 7           Identification and Classification of the Subsidiary Which
                 Acquired the Security Being Reported on By the Parent Holding
                 Company:

                 Not applicable

Item 8           Identification and Classification of Members of the Group:

                 Not applicable

Item 9           Notice of Dissolution of Group:

                 Not applicable

Item 10          Certification

                 Not applicable



                                    SIGNATURE

             After  reasonable  inquiry  and to the  best  of my  knowledge  and
belief,  I certify  that the  information  set forth in this  statement is true,
complete and correct.


                                           SMITH INVESTMENT COMPANY


                                           /s/ Bruce M. Smith
                                           Bruce M. Smith, Chairman & CEO
                                           February 2, 1999


                                           /s/ Lloyd B. Smith
                                           Lloyd B. Smith
                                           February 2, 1999


                                           /s/ Arthur O. Smith
                                           Arthur O. Smith
                                           February 2, 1999