The next attempt to destroy the noxious smell of the liquid, without destroying its bleaching property, was the addition of lime to the liquid. Mr Henry of Manchester was one of the first persons who thought of this addition. On the floor of his air-tight cham bers rested a stratum of thin cream of lime, through which the goods were passed by means of a wince ; and were afterwards exposed, an quitting the liquor, to oxymuriatic acid gas. Hence the oxymuriate of lime was formed upon the cloth. But this method was objectionable in the case of some coloared goods, the colours of which were injured or destroy ed by that earth. It admitted, therefore, of only a partial application.
Other persons made similar attempts, but none of them appear to have been attended with success. But Mr Tennant of Glasgow, after a great deal of most laborious and acute investigation, hit upon the method of making a saturated liquid of oxymuriate of lime, which was found to answer perfectly all the purposes of the bleacher. This was certainly a most important improvement. Without it, the prodigious extent of business carried on by some of our bleach ers could not possibly have been transacted. To give some idea of the rapidity with which bleaching is conducted according to the new process, we may mention the following fact, which we state on what we consider as very good authority. A bleacher in Lancashire received 1400 pieces of grey muslin on a Tuesday, which on the Thursday immediately fol lowing were returned bleached to the manufacturers at the distance of 16 miles, and they were packed up and sent off on that very day to a foreign market. The quick return of capital which is thus made is a benefit entirely to be ascribed to the new mode of bleaching.
In the year 1798, Mr Tennant took out a patent for his new invention, and offered the use of it to practical bleachers, for a fair and reasonable portion of the savings made by its substitution for potash, then in general use. Many of the bleachers, how ever, used it without paying him, and a combination was formed to resist the right of the patentees. In December 1802, Mr Tennant and Company brought an action for damages against Messrs Slater and Varley, the nominal defendants; but who, in fact, were backed and supported by a combination of al most all the bleachers in Lancashire. In conse quence of this action, the patent right was set aside by the verdict of a jury and the decision of Lord Ellenborough, who used very strong language a gainst the patentees. The grounds of this decision were, that the patent included a mode of bucking with quicklime and water, which was not a new in vention. It was decided that, because one part of
the patent was not new, therefore the whole must be set aside. Had the writer of this article constituted the jury, the verdict would have been very different. Lime was indeed used previous to the patent of Mr Tennant ; but it was employed in a quite different manner from his, and he would have allowed all of them to continue their peculiar method without any objection or injury to his emolument. If the very same process as that of Mr Tennant was employed before he took out his patent, there could be no doubt that the process originated with him, and that those who used it had been induced to do so from the information which they derived from him. In the opinion of the writer of this article, Mr Tennant was hardly used, and the words employed by Lord Ellenborough were quite inapplicable to him. But when a very powerful combination is formed against any individual, the sentiments with which they are actuated propagate themselves with rapidity, and it is difficult for the. most upright jury to avoid being swayed by prejudices so much the more formidable, because their existence is not perceived.
In consequence of this decision, the use of liquid oxymuriate of lime in bleaching was thrown open to all, and appears now to be universally employed by all the great bleachers in Britain. Mr Tennant, thus deprived of the fruits of several years- of anxious and laborious investigation, advanced a step farther, to what may be considered as the completion of the new method. This consisted in impregnating quick lime in a dry state with oxymuriatic acid. He had taken out a patent for this on the 13th of April 1799, and his right fortunately was not contested. He began his manufactory of solid oxymnriate of lime at_first upon a small scale, which has been ever since gradually extending, and is now very consider able indeed. During the whole period of the dura tion of his patent, he laboured-under great disadvan tages. The oxymuriatic acid as with which the lime was impregnated, was obtained from common salt. Now, his patent did not extend to Ireland, in consequence of which, manufactures of dry oxymu. riate of lime were established in that kingdom. In Ireland, the manufacturer obtained his salt-duty free, while in Scotland Mr Tennant was obliged to pay a duty of 7s. 6d. pr bushel. Such, however, was the superiority of the methods employed by Mr Tennant, that he was able to compete with the Irish manufacturers in their own country.