lighting by means of storage cells. In fact the cells discharged at a lower potential difference than that produced in charging, so would not work. The patent was invalid because useless. A critical experiment would have revealed the defect. Lane Fox v. Kensington, post, p. 345. The successful manufacture of a new dye depended for success on the presence of iron at a certain stage of the process. This was furnished by the use of an iron vessel. The patentee never discovered this essential until the trial of an action for infringement. The patent was invalid for insufficiency of directions. Badische Anilin, &c. v. La Soc. Chimique des Usines du Rhone, post, p. 405. The Complete Specification. The time allowed for leaving the complete specification is nine months from the date of application.' But where the circumstances justify it, an extension of one month may be allowed by the Comptroller, on a proper application being made to him, stating and proving the circumstances and grounds of the application.3 If the complete specification be not lodged within the nine or ten months (as the case may be) the application will be deemed to be abandoned. The provisional specification of an invention that has been abandoned is not now open to public inspection.5 In the case of applications made after the date on which sect. I of the Act of 1902 (post, p. 523) comes into operation, the complete specification must be lodged within six months (unless extended by the Comptroller to seven), or the application will be deemed abandoned. The complete specification is required to discharge two functions. It must particularly describe and ascertain the nature of the invention, and in what manner it is to be performed. This branch of the subject, including the relation of the complete to the provisional has already been discussed (ante, Chap. V. p. 52). There remains, however, to notice the requirements as to the form of the specification. An application may be made in the first instance accompanied by a complete specification. This course is pursued where the invention is of such a nature that no experiments are necessary, or 1 Sect. 8 (1) of the Act of 1883, post, p. 487. 2 Sect. 3 of the Act of 1885, post, p. 515. 3 Rule 10, post, p. 528. Sect. 8 (2) of the Act of 1883, post, p. 487. 5 Sect. 4 of the Act of 1885, post, p. 516. where such can be made without risk of publication of the invention. This usually happens when the experiments have been made abroad. The following are the directions given in the Patent Office Circular of Information. Where a provisional has been lodged par. ix. (a) does not apply: Application accompanied by Complete Specification. (ix.) An application accompanied by complete specification consists of(a) The Application Form A or (for inventions communicated from abroad) A1, or (for applications under the International and Colonial arrangements) A2, stamped £1, duly filled in, and signed by the applicant or applicants; and (b.) The complete specification, Form C, stamped £3, and unstamped duplicate. (x.) The complete specification must be begun upon Form C (bearing a £3 stamp), and continued, if necessary, on foolscap paper. The duplicate must be an exact copy, but unstamped. The specification should contain a full and detailed description of the invention, of such a nature that the invention could be carried into practical effect by a competent workman from the directions of the document alone.1 The specification must be accompanied by drawings if required. See Rules 18-24, post, p. 529. It is necessary to make a distinct and proper statement of claims in the complete specification. The claims should form in brief a clear statement of that which constitutes the invention, and inventors should be careful that their claims include neither more nor less than they desire to protect by their patent." In the claims the actual novelty or novelties in the structure, or composition, or processes, or apparatus, should be stated.3 Claims are not intended to be made for the efficiency or advantages of the invention.* Unless the complete specification is accepted within twelve months (or with enlargement of time, thirteen, fourteen, or fifteen months) from the date of application, the application becomes void, and cannot be further proceeded with. The complete specification must begin with the title. The nature and function of the title are explained ante, pp. 53-106. The title should be the same as in the application and provisional, and should not include fancy names, the inventor's name, or the terms 1 This condition is fully discussed and illustrated ante, pp. 72-78. Ante, pp. 89, 90. • Claims are only for the invention; as to its extent, see ante, pp. 11, 61. "patent" or "etc." (ante, p. 107). The sufficiency of titles is further illustrated under Amendment of Specifications, post, pp. 167, 170. After the title there is frequently inserted a short statement of the objects of the invention, or of the difficulties that it is intended to overcome. The uses and advantages need not be mentioned at all (ante, pp. 11, 61), nor the objects to be achieved, but they are frequently inserted in the body of the specification to show the extent of the claim. A statement of the difficulties to be overcome involves a statement of prior knowledge. There is no objection to an honest statement of the state of knowledge of the day, which, of course, the applicant makes at his own peril; if incomplete it may lead to a wide construction being put on his claims, and so tend to invalidate the patent, or if misleading, will invalidate the patent.1 He may if he choose state generally defects in earlier processes or inventions, but if such a statement be not made in a specification when originally drawn, an applicant will not be allowed by amendments to subsequently introduce a statement that an invention (for which a prior patent existed) had certain disadvantages. In making such a statement previous specifications may be referred to, but not in such a manner as to give any particular construction to them; they should speak for themselves.3 Theories should be omitted, and enunciation of principles upon which the invention is based, unless such mention of principles be an easy way of pointing out the extent of the invention claimed (ante, p. 60). The form of the specification will depend on the subject-matter of the invention; for instance, in the case of dyes, the chemical principles are frequently shortly stated, and then a series of practical examples given; in the case of improvements, references are frequently made to prior specifications; 5 mechanical inventions are necessarily described at length, first in general terms and then in detail, with references to drawings. Directions as to details in the preparation of the specification and drawings are given in the Patent Rules numbered 17-24, post, Pp. 529, 530, 531. 1 Atherton's Patent, 6 R. P. C. 547. See also Owen's Patent, ante, pp. 75, 76. 2 Hampton & Facer's Patent, Gr. L. O. C. 14; Guest & Barrow's Patent, 5 R. P. C. 316. 3 Atherton's Patent, 6 R. P. C. 548. 4 See for illustration, post, pp. 363, 405. 5 Instances will be found post, pp. 233, 370, 453, 463. • For illustrations see post, pp. 277, 283, 300, 358, 407, 414, 437, 463. So The claims are drawn entirely at the risk of the applicant. long as sect. 5 (5), post, (p. 486), is in form complied with, there is no jurisdiction on the part of the Comptroller-General or the Law Offices to require amendment, or to refuse the application because the claim is not for the invention as described.1 But the usual practice is to call the attention of the parties, in cases of opposition, to the points to which objection might exist and leave it to them to suggest and consent to amendments.2 The applicant should never presume on this practice, as it is his duty, in the first instance, to make the proper claims; for amendments are not allowed as of course, and should only be made somewhat sparingly. Where claims have been disallowed it has been in cases of opposition on some statutory ground, the specification being accepted subject to a claim being struck out as a condition (see Opposition, post, p. 135). Although there can be only one invention described in the specification, there may be several claims, either principal for different parts, or some subsidiary." Two difficulties always confront the applicant in framing his claims. No matter how thorough his search may be as regards prior specifications British and foreign, and other specifications within the realm, yet there may exist things made and used which may subsequently be brought to light and either invalidate the patent for want of novelty, or have the effect of narrowing the claim by the operation of the rule of benevolent construction (ante, pp. 93–96). For illustrations, see Lyon v. Goddard, post, p. 358. Morris v. Young, post, p. 371. To meet this difficulty he should frame his claims as distinct and narrow as possible, confining them to the essential elements of his invention.6 On the other hand, he cannot foresee the course that will be taken by members of the public in order to get the benefit of the 1 Smith's Patent, Gr. 268; Everitt's Patent, Gr. L. O. C. 27; Newman's Patent, 5 R. P. C. 277. * Newman's Patent, 5 R. P. C. 277; Webster's Patent, 6 R. P. C. 164. Garnet's Application, 16 R. P. C. 156; Thomas and Prevost's Application, 16 R. P. C. 70. * Sect. 33 of Act of 1883, post, p. 498. See ante, pp. 58, 63. * See remarks of Lord Herschell in The Lancashire Explosives Co. v. Roburite, &c., post, P. 397. I knowledge he gives in his specification without infringing his claim ; nor can he foresee that his invention may be used for purposes other than those for which it was originally devised. To avoid the unfair use of his invention his claims should be as wide as possible. Two methods are pursued in order to achieve these apparently inconsistent objects; each has its advantages and defects. One is to make a series of claims, some wider (as, for instance, for a process consisting of the application of certain principles in a certain manner, or by means of a certain machine or combination) and others narrower (as, for instance, for the mode of application, the machine, or combination itself); the latter being in most cases subsidiary claims (ante, p. 58). The advantage of this method is, that if it be subsequently discovered that, owing to the state of public knowledge, or to prior grants, the wider claims would invalidate the patent, they may be struck out by disclaimer, and the patent remain valid as regards the remaining claims. The defect of this method is that it tends to defeat the object for which it is pursued. For the juxtaposition of such claims, unless they be clearly expressed, affects the construction of them, and the tendency is, in cases of doubt, to construe the larger ones wider, and the minor ones narrower, than if each stood alone (ante, p. 92). The second method of attempting to achieve these inconsistent objects is to draft the claims in a neutral manner, so that when subsequent events make it advisable to avoid alleged anticipation, reliance may be placed on the doctrine of Benevolent Construction (ante, pp. 93-96); or, if no anticipation be alleged, the doctrine of Equivalents (ante, pp. 96–99) may be invoked to cover the alleged infringement. The objections to this method are, that it tends to obscure the patentee's rights, so promoting litigation; and that if it appear that the claims have been drawn intentionally in an ambiguous manner, the patent will be invalid (ante, p. 59). When an application is accompanied by a Complete Specification it is referred to an examiner and dealt with in the same way as a Provisional (ante, p. 108). Illustration. Application was made for a patent for "improvements in casks and tubs." The complete stated that the invention was applicable to barrels, |