<?xml version="1.0"?><ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>3</documentType><periodOfReport>2003-07-25</periodOfReport>
    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000046989</issuerCik>
        <issuerName>HERCULES INC</issuerName>
        <issuerTradingSymbol>HPC</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001178438</rptOwnerCik>
            <rptOwnerName>GERRITY THOMAS P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>HERCULES PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>1313 N. MARKET ST.</rptOwnerStreet2>
            <rptOwnerCity>WILMINGTON</rptOwnerCity>
            <rptOwnerState>DE</rptOwnerState>
            <rptOwnerZipCode>19894-0001</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><footnotes></footnotes><remarks></remarks><ownerSignature><signatureName>/s/ Israel J. Floyd
Acting As Attorney In Fact for Thomas P. Gerrity</signatureName><signatureDate>2003-09-02</signatureDate></ownerSignature></ownershipDocument>

