proceeds accrued from the subject ma er a er delivery shall belong to the buyer, unless otherwise agreed by the par es. Ar cle 631 Where a contract is rescinded due to the inconformity of the principal subject ma er with the agreed requirements, the e ect of the rescission shall be e ec ve against the accessory subject ma er. Where a contract is rescinded due to the inconformity of the accessory subject ma er with the agreed requirements, the e ect of the rescission shall be e ec ve against the principal subject ma er. Ar cle 632 Where the object of a contract is composed of several subject ma ers, if one of them fails to conform to the requirements agreed in the contract, the buyer may rescind the part of the contract in connec on with that subject ma er. However, where separa on of the said subject ma er from the other subject ma ers is to markedly harm the value of the subject ma ers of the contract, the buyer may rescind the contract in connec on with the mul ple subject ma ers concerned. Ar cle 633 Where the subject ma ers are to be delivered by installment, if a seller fails to deliver one lot of the subject ma ers, or has delivered the lot in a manner not in conformity with the agreement, so that the purpose of the contract in connec on with the said lot cannot be achieved, the buyer may rescind the part of the contract in connec on with the said lot. Where a seller fails to deliver one lot of the subject ma ers, or delivered the lot in a manner not in conformity with the agreement, so that the subsequent delivery of the remaining lots cannot achieve the purpose of the contract, the buyer may rescind the part of the contract in connec on with the said lot and the remaining lots. Where a buyer has rescinded a part of the contract in connec on with one lot of the subject ma ers, if the said lot and any other lot are interdependent on each other, the buyer may rescind the contract in connec on with all the lots disregarding whether they have been delivered or not. Ar cle 634 Where a buyer under an installment contract fails to make payment and the unpaid amount reaches one- h of the total price, if the buyer s ll fails to pay the due installment amount within a reasonable period of me a er being demanded, the seller may request the buyer to pay the total sum or he may rescind the contract. The seller who rescinds the contract may request the buyer to pay a fee for the use of the subject ma er. Ar cle 635 The par es to a sale by sample shall seal up the sample and may make speci ca ons of its quality. The subject ma er delivered by the seller shall be iden cal in quality with the sample and its speci ca ons. Ar cle 636 Where a buyer to a sale by sample is unaware of the sample's hidden defects, even if the subject ma er delivered is iden cal with the sample, the quality of the subject ma er delivered by the seller shall s ll conform to the general standard for the same category of goods. Ar cle 637 The par es to a sale on trial use may agree on a period for trial use of the subject ma er. Where there is no agreement between the par es on the period for trial use or the agreement is unclear, if the period for trial use cannot be determined according to the provisions of Ar cle 510 of this Code, it shall be determined by the seller. Ar cle 638 A buyer to a sale on trial use may purchase or refuse to purchase the subject ma er within the period for trial use. Where, upon expira on of the period for trial use, the buyer makes no indica on as to whether to purchase it or not, the buyer is deemed to have purchased the subject ma er. If a buyer to a sale on trial use has, within the period for the trial use, already made par al payment or has sold, leased, created a security interest in the subject ma er, the buyer is deemed to have agreed to purchase it. Ar cle 639 Where there is no agreement between the par es to a sale on trial use on the fee for the use of tt tt tt ti tt tt tt tt ti fi ti tt tt tt ti tt ti tt tt ti ti ti ti ff ti tt tt ti tt ff ti ft ti ti ti tt tt ti tt ff ft ti ti tt ti ti ff ti ti tt ft fi tt ti ti ti ti fi tt ti ti ti ti ti ti ti ti ti ti 70