ported, early obtained validity as new in this realm, though invented abroad, and it would appear that if an Englishman first publish his invention abroad, he is still entitled to take out a British patent for it. Not only are many useful foreign inventions hereby obtained, but the door is thus closed to the pretence, which would often be alleged in an action for infringement, that the thing is not new because known in some distant country.

24. When for new substance patent should be for the composition. When the object to be patented is some new substance, the patent should be for the composition. without regard to the process, since that, though probably new, is only useful in producing the new substance.

25. When for new machine patent should be for the mechanism. When the object is a new machine or means for producing substances, the patent must be for the mechanism.

26. When for improved machinery patent may be for whole, excepting the old parts, or simply for the improvement.-When the object is for improved machinery the patent may be for the whole, protesting against any claim for the old parts, or simply for the improvement.

27. Slight combination producing new results patentable. A very slight combination of means will support patent provided the instrument is new and useful.

28. When principle new, patent may be for all combinations of it.-When a principle is new, a patent may be had not only for some particular mode of carrying it out, but for every mode by which it might be carried out.

29. No rule can be given for amount of ingenuity necessary to support a patent.-No general rule can be

laid down as to the amount of ingenuity in an invention necessary to support a patent. In new cases all that can be done is to study carefully analogous decisions, and be guided by those which nearest approach to the doubtful case.

30. Deceit vitiates a patent.—Any evidence of deceit apparent on the face of a patent is liable to vitiate it; for instance, when any ingredient is mentioned as essential when it is not so, nor even useful.

31. In invention resulting from two minds, both must be included in patent.-When an invention results from the combined operation of two minds, the patent must be in the joint names of the inventors.

32. Material part of an invention being made by another vitiates the patent.—A patentee owing a material part of his invention to another forfeits his patent; but this does not extend to the point of forbidding him to employ workmen or others to assist in perfecting an invention, the principle of which he already has contrived. The case is very different where the patentee is merely the employer of him making the invention, for then the patentee was not the first and true in

ventor.

33. Provisional specification. Government gives no guarantee. The provisional specification to a patent should be couched in general terms, but must be strictly confined to the invention, and be so framed as to include every application which is intended to be made of it. Although all patents are referred to the law officers for examination, this implies no guarantee on the part of the Government; therefore every means should be taken to make both title and specification correct. But it is by no means desirable that these preliminary documents should enter too much into

detail, lest rivals about to specify should obtain a clue to the invention to the prejudice of the inventor. Besides, the more general the provisional specification is made the more latitude is allowed for the introduction of applications in the complete specification which may suggest themselves during the six months of provisional protection.

34. Patent and specification linked by title.-Patent and specification are linked together by the title. The title and specification must be read together, and the latter must support the former.

35. Inappropriate or insufficient titles.--Many patents have been vitiated by inappropriate or insufficient titles, which did not give an intelligible idea of the invention. One instance has been frequently given of a brush described in the title as a tapering brush, whereas the invention consisted in the unequal length of the bristles. Another was a patent entitled, an improved method of drying and preparing malt, whilst the invention was a colouring matter for beer, obtained by submitting malt to a high temperature. Another title was held as being too general because the invention being for an improvement in the old street lamp, the title designated it as an improved method of lighting cities, towns, and villages. A patent was declared void whose title described it as a machine for giving an edge to knives, razors, scissors, &c., because it was not applicable to scissors.

36. Complete specification.-But whilst the provisional specification may safely be left as general as possible, consistent with correctness, the utmost attention must be directed to the complete specification, and it is here especially that the skill and experience of the professional patent agent will be useful to his client.

37. Secret must be fully disclosed. It is a fundamental rule that the secret of the invention must be so disclosed that men of common understanding, with a moderate knowledge of the art to which the invention relates, may be able thereby to carry the object of the invention fully into effect.

The de

38. Extraneous matter must be excluded. scription must be confined to the invention. No extraneous matter, however learned, must be introduced. to darken it. Avoiding complexity, it must not be so concise as to become obscure. It must be minute without perplexity, and luminous without being overwrought.

39. Ambiguous specification bad.—A specification is bad where the terms are ambiguous, where necessary descriptions are omitted, where some parts claimed are not original (unless afterwards disclaimed), where things are put in to mislead, where the drawings are incorrect, where one of different ways for effecting the object of the invention fails, where one of several effects specified is not produced, and where the things described are not the best known to the patentee. A patent for improvements in sail-cloth was declared bad on the ground of ambiguity, because, taking the title, patent, and specification together, it was difficult to say whether the word whatever referred to the total exclusion of starch, or whether, when combined with the words" without any starch," it was merely a description of the thread of the sail-cloth which had been improved. Another was declared unintelligible, and consequently invalid, because it directed that fossil salt should be used, fossil salt being a genus having many species, only one of which, sal gem, being suited to the purpose. Again, a specification directed that

"the purest and finest chemical white lead" should be used. Now no article was known in the trade under that designation, and the article intended to be used was imported from Germany, and only to be had in one or two colour shops in London. The specification was held insufficient.

40. Such words as "for other useful purposes," &c., to be avoided.It is a great error to suppose that the introduction of the words "for other useful purposes," "other materials may be used," or "any other substance from which the thing can be obtained," gives greater breadth or security to a patent. Such expressions, besides being perfectly useless, are likely to throw doubts on the reality of the invention, and to hazard the validity of the patent on the ground of obscurity and incorrectness. In the case of a patent for paper-making the plaintiff was nonsuited, because he said in his specification "the cloth may be made of any suitable material, but I prefer it to be made of linen warp and woollen weft," whereas he was not aware of any other substance to answer the purpose. Of course this doctrine of ambiguity might be pushed too far. Novelty, clear good faith, and reasonable distinctness are are required from an inventor.

41. Patentee may abandon parts of invention. — A patentee, after reasonable trial, may, without vitiating his patent, lay aside any part of a method described in his patent should he find that such part is unnecessary.

42. Drawings.-Drawings, models, &c., are not absolutely necessary, and, indeed, where the subject can be clearly described without, they are better omitted. They are, however, easy means of illustration, and therefore generally adopted. Great latitude has been allowed with respect to drawings. If a common mechanic can make

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