20. Where an annuity is payable in goods, either by law, by treaty, or at the request of the Indians, such goods will be purchased by contract, to be based upon proposals previously issued. Such proposals will be issued under the direction of the Secretary of War, and by a person to be designated by him, and will give at least thirty days' previous notice. Such notice will specify the amount required, the time and place of delivery, and will describe, as minutely as practicable, the kinds and quality of the various articles required. In determining the kind and quality of the articles, regard must be had to the habits and tastes of the tribe for whom such articles are designed. Of this, the proper superintendent, agent, or sub-agent, must judge, unless the Indians themselves shall decide the matter. With this view, the subject will be explained to them at every annuity payment, and, if they see fit, the various articles, in the proportions to be indicated by them, will be purchased accordingly for the next payment. The mode of determining the quantity will be as follows: if, for instance, the annuity due to the tribe be ten thousand dollars, the proposals will state that such a portion of that amount, say two thousand dollars, will be for blankets--such a portion, say two thousand dollars, for strouds--such a portion, say one thousand dollars, for calicoes--such a portion, say five hundred dollars, for powder--such a portion, say five hundred dollars, for tobacco--and so on; designating the proportional part which shall be assigned to each particular object. The goods will be transported to the place of delivery at the sole expense of the contractor, and kept there at his risk until delivered by the proper officers to the Indians. In all cases, patterns of blankets, strouds, and such other articles as cannot be described with sufficient precision, will be deposited at some convenient place for inspection, and the articles to be furnished will be in conformity therewith. If they are not in such conformity, they will be liable to the proceeding subsequently described herein.