United Kingdom House of Lords Decisions

Astley, conceiving that he had made a discovery of an improved mode of manufacturing sal ammoniac, obtained a patent, of which the specification was in these terms:

“I, the said Joseph Astley, do hereby declare, that the nature of said invention is described in manner following: That is to say, I prepare the salt called muriate of magnesia, or the muriate of alumine, or one or other of the metallic muriates, or any of the combinations of muriate acid from which the acid is capable of being disengaged by heat. What I commonly employ is the muriate of magnesia, which may be procured in different ways, and very easily and economically from the mother liquor of salt-pans, called bittern or salt oil. The other salts contained in this being separated by evaporation and crystallization, I use

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the muriate of magnesia, prepared by this or by any other process, or any of the other articles above mentioned, either in a liquid or in a solid form. In the former way, I cause animal substances of all kinds, or such vegetable or animal substances as afford ammonia or volatile alkali by distillation, to be impregnated with liquor, holding any of the said salts in solution, which liquor I use in proportions, varying according to the particular kinds of salt employed, the degree of concentration of the liquor, and the nature of the animal or other substances to be impregnated, the object being to obtain the acid and alkali developed in the subsequent operation, in proportions approaching as nearly as possible to mutual saturation. I afterwards dry the animal or other substances thus impregnated on a heated floor or otherwise, and either distil them by the heat of a furnace, in a retort or still, with one or more receivers adapted to collect the products, or else burn them in a kind of furnace or kiln (which may be variously constructed,) the products of the combustion being collected in chambers or receivers adapted to the purpose, which chambers or receivers must have an opening or vent to maintain the current of air necessary for the combustion. The previous drying is not an essential part of the process, and in some cases may be dispensed with, though it will generally be found expedient. When I use the salt in a solid form, that is, either crystallized or dried by evaporation, the process is merely to mix it in such state with the animal or other substances, and proceed as above; but I find that the object is effected more easily and completely by using the salt in the state of solution, or, instead of impregnating the animal or other substances themselves with any of the saline matters above described, I cause substances of any description whatever (provided there be nothing in their nature rendering them chemically or mechanically unfit to serve as vehicles for such purpose) to be impregnated with such saline matter, and treated as above described, along with the animal or other substances, the fundamental object of all these processes being to present the acid and alkali to each other in their nascent state, as they are respectively developed from the said saline matter, and the animal or other substances by heat, by which means we obtain, on the one hand, a more complete decomposition of the said salts, by help of the divellent affinity of the ammonia, and we prevent, in a great measure, on the other hand, the destruction of the alkali by combustion, which would otherwise occasion great loss in the burning of the materials. In all the processes here described the product is the same, being muriate of

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ammonia or sal ammoniac, partly dry and partly in solution, which is afterwards to be crystallized and sublimed according to the ordinary processes, or which may be used for some purposes without undergoing these subsequent operations. It may be proper to state, that I do not here lay claim to the exclusive privilege of procuring muriatic acid from the salts above mentioned by distillation, as it has been long known to chemists that several of them are decomposible by heat. My claim is to the modes of effecting this decomposition, as here explained, which will be found to possess, besides the advantage already mentioned, that of avoiding the inconveniences with which the operation of distilling the muriate salts in question (particularly the muriate of magnesia) by themselves is always attended.”

Astley, alleging that Taylor had clandestinely discovered his mode of operation, and had violated his patent, brought an action of damages and of interdict against him. In defence, Taylor stated, 1. That he had not violated the patent. 2. That the specification was insufficient; and, 3. That the alleged invention was not valuable, because it consisted of a mere modus operandi,—well known materials being used for the production of a well known commodity. After allowing a condescendence and answers, the late Lord Meadowbank found “nothing correctly or relevantly stated, on the part of the defender, to impede the pursuer's right to the exclusive use of the process for manufacturing sal ammoniac, as described in the specification protected by the patent, and particularly such use of the muriate of magnesia contained in the bittern or refuse produced in the preparation of common salt from sea water;” and allowed to Astley a proof of his allegations as to the violation of his patent. Taylor having reclaimed, the Court appointed Dr. Hope to visit the works of the parties respectively, and to report. Dr. Hope having reported that the process was original and useful, but that the specification was inadequate, the Court, on the 27th of November 1813, “sustained the objection to the title of the pursuer, in respect of the want of due specification in his patent; and therefore alter the interlocutor reclaimed against, dismiss the action, and decern; but find no expenses due.” Against this judgment Astley reclaimed, and offered to prove, by the evidence of men of skill, that the specification was sufficient to enable them to perform the operations for which the patent was granted. The Court having allowed him to prove accordingly, he, in support of this allegation, adduced Dr. Murray, Professor Leslie, Mr. Charles Macintosh, and Mr. Charles Tennent of Glasgow, Dr. Thomas Thomson, Mr. Tilloch, Mr. Nicholson, Mr. Accum,

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