And it is hereby further covenanted and agreed by and between the parties hereto, that the rebates hereinbefore provided for the party hereto of the first part, may be made to any other party who shall furnish an equal amount of transportation, and who shall possess and use works, means, and facilities for carrying on and promoting the petroleum trade equal to those possessed and used by the party hereto of the first part. ARTICLE FOURTH And it is hereby further covenanted and agreed by and between the parties hereto, that the party hereto of the second part shall at all times co-operate, as far as it legally may, with the party hereto of the first part, to maintain the business of the party hereto of the first part, against loss or injury by competition, to the end that the party hereto of the first part may keep up a remunerative, and so a full and regular business, and to that end shall lower or raise the gross rates of transportation over its railroads and connections, as far as it legally may, for such times, and to such extent as may be necessary to overcome such competition. The rebates and drawbacks to the party of the first part to be varied _pari passu_ with the gross rates. ARTICLE FIFTH It is hereby mutually agreed by and between the parties hereto that for the purpose of meeting such exigencies as may from time to time require change of the rates of transportation herein provided, each party, on ten days’ written notice from the other, shall appoint a person on behalf of such party, and the two persons thus appointed, shall have power to change and adjust the rates, which shall go into effect on being approved by the said parties hereto. ARTICLE SIXTH It is further mutually agreed by and between the parties hereto that the gross rates of freight to the party hereto of the first part shall at all times be kept as near to the net rates as is consistent with the interests of the party hereto of the first part, and that whenever in the judgment of the party hereto of the first part it is expedient to lower the rebate below the rate above specified, it may do so, and from time to time raise the same again, not, however, above the rate hereinbefore specified. The party hereto of the first part, from time to time shall notify the party of the second part in writing of the change required, whereupon the party hereto of the second part shall forthwith make a corresponding change of such gross rates. ARTICLE SEVENTH It is further mutually agreed by and between the parties hereto, that this agreement shall continue and remain in force for the period of not less than five years, and shall not then, nor thereafter terminate, until one of the parties shall have given twelve months’ written notice to terminate it.