117. DRAWINGS ATTACHED TO THE PATENT AS PART OF THE SPECIFICATION.-When the nature of the case admits of drawings, the applicant shall furnish one copy, signed by the inventor or his attorney in fact, and attested by two witnesses, which shall be filed in the Patent Office; and a copy of said drawings, to be furnished by the Patent Office, shall be attached to the patent as part of the specification. (Act of July 8, 1870, § 27.)

118. RULES OF THE PATENT OFFICE CONCERNING THE PREPARATION OF DRAWINGS.-Drawing must be on thick, smooth drawing paper, sufficiently stiff to support itself in the portfolios of the office. It must be neatly and artistically executed, with such detached sectional views. as to clearly show what the invention is in construction and operation. Each part must be distinguished by the same number or letter whenever it appears in the several drawings. The name of the invention should be written at the top, the shortest side being considered as such. This drawing must be signed by the applicant or his attorney, and attested by two witnesses, and must be sent with the specification. Tracings upon cloth pasted on

thick paper will not be admitted. Thick drawings should never be folded for transmission, but should be rolled. (Patent Office Rules, July, 1870.)

The following rules must be observed in the preparation of the drawings, in order that they may be photolithographed:

The paper must be thin Bristol board or thick drawing paper, with a smooth or calendered surface. The outlines must be executed in deep black lines, to give distinctness to the print. Pale ashy tints must be dispensed with.

In shading, lines of black ink should be used, and such lines should be distinct and sharp and not crowded. Brush shadings or shadows will not be permitted.

All colors except black must be avoided in the drawings, lettering, and signatures; violet and purple inks must not be used.

No agent's, attorney's, or other stamp must be placed, in whole or in part, within the margin.

The sheet must not be larger than ten inches by fifteen, that being the size of the patent. If more illustrations are needed, several sheets must be used. (Ib.)

119. COPIES FURNISHED BY THE OFFICE.-Copies of drawings of patents issued after January 1, 1869, will be furnished to any one at the uniform rate of twenty-five cents per sheet of standard size. (Ib.)

Copies of drawings of patents issued prior to January 1, 1869, which can be photo-lithographed, will be furnished at twenty-five cents per sheet, when ten or more copies are ordered. Single tracings of such drawings, or less than ten, will be furnished at the cost of making them. One hundred copies or more will be furnished at $10 per hundred. (Ib.)

The duplicate drawing to be attached to the patent will be furnished by the office without charge, and will be a photo-lithographic copy of the thick drawing. (Ib.)

Written or printed copies of any records, books, papers, or drawings belonging to the Patent Office, and of letters patent under the signature of the Commissioner or Acting Commissioner, with the seal of office affixed, shall be competent evidence in all cases wherein the originals could be evidence, and any person making applica tion therefor, and paying the fee required by law, shall have certified copies thereof. And copies of the specifications and drawings of foreign letters patent, certified in like manner, shall be prima facie evidence of the fact of the granting of such foreign letters patent, and of the date and contents thereof. (Act of July 8, 1870, § 57.)

The officer intrusted to give copies of papers or drawings in patent cases has no concern with the purpose for which asked. The policy of the law rather requires than forbids that copies should be given when applied for. (1 Opinions Attorneys General, 171.) And it is the duty of the Commissioner of Patents to give authenticated copies to any person demanding the same, on the payment of the legal fees; and for his refusal an action will lie against him. (Boyden v. Burke, 14 How., 583.) But a demand accompanied by rudeness and insult is not a legal demand. (Ib.) A subsequent and proper demand cannot, however, be refused on account of prior misconduct or to enforce an apology. (Ib.) Copies cannot be taken by third parties; they must be taken by the proper officer and the fees paid therefor. (2 Opinions of Attorneys General, 456.)

120. OFFICE OF THE DRAWING AND ITS RELATION TO THE

SPECIFICATION. The object of annexing drawings is to explain the mode of constructing the subject of the patent. It has been settled that the drawings constitute a part of the specification, when annexed thereto, and may be used to explain the otherwise imperfect description in the specification; so that the description may be partly in writing and partly in drawing; and if, by a comparison of words and drawings, the one will explain the other sufficiently to enable a skillful mechanic to perform the

rk, and to show that it is the invention claimed, the specification will be sufficient. (Wilber v. Beecher, 2 Blatchf., 132.) The drawings need not be mentioned in the specification, but it is sufficient if the patentee puts them and written references on file with the specification. (Emerson v. Hogg, 2 Blatchf., 1.) And a drawing, filed sometime after the recording anew of a patent, under § 1, act of March, 1837, is admissible in evidence, but is not to be deemed or taken as part of the specification, nor to be used for correcting any material defect therein. (Winans v. Schenectady and Troy Railroad, 2 Blatchf., 299; Curtis on Patents, 262.)

If the drawings show an element of the invention which the patentee has not included specially in his claim, it is evidence, nevertheless, that it was a part of his invention, and he or his assignee has a right to incorporate that element in a reissued patent; and an ambiguity in the description may be removed by reference to the drawings, which may be examined to determine the dimensions of the parts, when dimensions become material. (Swift v. Whissen.)

The drawing may also be referred to for the purpose of adding something to the specification or claim not spe

cifically contained or mentioned therein, e. g., to describe or show the existence of rollers in a machine when they are not described in the specification. (Washburn v. Gould, 3 Story, 133.) But it need not delineate old machinery connected with the new invention when no change in such old machinery enters into the new invention. (Emerson v. Hogg, 2 Blatchf., 9.)

121. DESCRIPTION OF DRAWINGS.-If drawings are used, they should be referred to in the commencement of the specification. When they are disposed in several sheets, it is often advisable to number the "figures" consecutively throughout, and thus to avoid, in references, the use of double numbers, such as "fig. 2, sheet 1," by enabling the reader to find the drawings from one reference. (Macgregor, Language of Specifications, 64.)

122. LETTERS.-The capitals, A, B, C, &c., are usually employed to mark the larger parts of the drawings, and the small letters, a, b, c, &c., are applied to more minute parts. (1b., 65.)

Parts which are similar in construction, and differ only in position, are frequently denoted by the same letter with an affix, as A', A2, A3, representing, for example, the spokes of a wheel or pillars of a frame. (Ib., 65.)

123. Order of LETTERS.-With regard to the order of letters, it is not easy to lay down comprehensive rules, without incumbering those who would observe them by confusing restrictions. In some cases, where the actions of each part of the portion of the machine or process under description result immediately from another, and where no particular or lengthy description is required of one or other part in the nature of a digression, the nature