For the purposes of this chapter the kinds of spirits of turpentine defined in subdivisions (c), (e), and (f) of section 92 of this title and the rosin types heretofore prepared and recommended under existing laws, by or under authority of the Secretary of Agriculture, are made the standards for naval stores until otherwise prescribed as hereinafter provided. The Secretary of Agriculture is authorized to establish and promulgate standards for naval stores for which no standards are herein provided, after at least three months’ notice of the proposed standard shall have been given to the trade, so far as practicable, and due hearings or reasonable opportunities to be heard shall have been afforded those favoring or opposing the same. No such standard shall become effective until after three months from the date of the promulgation thereof. Any standard made by this chapter or established and promulgated by the Secretary of Agriculture in accordance therewith may be modified by said Secretary whenever, for reasons and causes deemed by him sufficient, the interests of the trade shall so require, after at least six months’ notice of the proposed modifications shall have been given to the trade, so far as practicable, and due hearings or reasonable opportunities to be heard shall have been afforded those favoring or opposing the same; and no such modification so made shall become effective until after six months from the date when made.

The various grades of rosin, from highest to lowest, shall be designated, unless and until changed, as hereinbefore provided, by the following letters, respectively: X, WW, WG, N, M, K, I, H, G, F, E, D, and B, together with the designation “gum rosin” or “wood rosin”, as the case may be.

The standards herein made and authorized to be made shall be known as the “Official Naval Stores Standards of the United States,” and may be referred to by the abbreviated expression “United States Standards”, and shall be the standards by which all naval stores in commerce shall be graded and described.