26--The drawings to be in duplicate, one copy on heavy parchment, the other copy on tracing cloth, the drawings to be made with india ink of best quality and with pen only, every line and letter must be black. The size of a sheet on which a drawing is made should be exactly 10x15 inches, one inch from its edges a single marginal line to be drawn, leaving the "sight" 8x13 inches. Within this margin all work and signatures must be included, one of the smaller sides of the sheet is regarded as its top, and measuring downward from the marginal line a space of not less than 1-1/4 inches is to be left blank for the insertion of Title, Name, Number and Date. 27--The scale to which a drawing is made should be large enough to show the mechanism without crowding, and more than one sheet may be used, if necessary, to accomplish this end. Letters and figures of reference should be carefully formed, and large enough to be plainly distinguished. If the same part of the invention appears in more than one view of the drawing, it must always be represented by the same character; and the same character must never be used to designate different parts. 28--No agent's or attorney's stamp, or advertisement, or written address, will be permitted upon a drawing. Should the application be found incomplete under the above rules and be returned from the Minister of the Interior for amendment, the same must be again filed within thirty days, if the applicant is a resident of the Hawaiian Islands, or within four months if residing in a foreign country; otherwise it will be barred, if interfering with another application filed during the interval and covering the same invention or improvement. THE MODEL. 29--A model will not be required as part of the application unless on examination of the case it shall be found to be necessary or useful; when, if so found, the Commissioner of Patents shall, in writing, notify the applicant, and action in the case shall be suspended until a model is furnished. 30--The model must clearly exhibit every feature of the machine which forms the subject of a claim of invention, but should not include other matter than that covered by the actual invention or improvement, unless it shall be necessary to the exhibition of the invention in a working model. 31--The model must be neatly and substantially made of durable material, metal being deemed preferable; but when a material forms an essential feature of the invention, the model will be constructed of that material. 32--The model must not be more than one foot in length, width or height, unless the Commissioner of Patents shall admit working models of complicated machines of larger dimensions. 33--Models belonging to patented cases will not be taken from the office except in the custody of a sworn employee especially authorized by the Commissioner of Patents. SPECIMENS.