ON BLEACHING. 137 



sidered to have received a bleaching ; the process of drying was in long 

 sheds, constructed mostly of wood, having openings at the sides with 

 sliding doors, and the pieces were suspended by hand upon lines of 

 railing, until they had become sufficiently dried by the atmosphere. When 

 taken down, every piece was neatly folded and compressed by screw 

 pressure, and this was deemed the finishing process before delivery at the 

 warehouse of the manufacturer. It is from such a beginning, and within 

 living memory, that I shall endeavour to trace the successive changes 

 which, in the course of sixty or seventy years, have led to the establishing 

 of that important branch of trade, now so intimately connected with the 

 cotton manufacture of this and other countries. The chemical preparations 

 originally adopted were somewhat primitive : the acids were derived, in 

 some extent, from an immersion of the cloth in sour milk, although the use 

 of a weak solution of sulphuric acid was the more prevailing practice. 

 The alkali, which is the basis of soap, was derived from the ashes of burnt 

 fern, sea-weeds, or other similar products. The oxygen of the atmosphere 

 was employed to whiten the grey fibre of the cloth, and a decoction of 

 sorrel was used to remove the stains and iron-moulds. About the year 

 1795, it had become obvious that the growing demands of commerce 

 required a more efficient agency than coidd be derived from such rude 

 elements. Severe pressure on the trade was felt from the enormous 

 amount and cost of labour required, the heavy expense and the inferior 

 quality of the drugs then in use, the rental paid by the bleacher, for so 

 large an extent of grass land as he found it necessary to occupy with the 

 exposure of his cloth to the atmosphere, together with the unavoidable 

 delay, uncertainty, and pecuniary losses, which were constantly occurring 

 from unfavourable weather and other causes. The manufacturer also 

 suffered greatly from the frequency of his disappointments, and the incon- 

 venience and loss he sustained from the necessity of having his capital in 

 goods lying three months in the bleach grounds. The emergency which 

 had now become so apparent had the effect of bringing out inventions and 

 improved processess. These succeeded one another with great rapidity, 

 and those proprietors of works who possessed intelligence and capital made 

 rapid progress ; although there were other instances in which the want of 

 capital or the absence of enterprise prevailed, and in these cases there 

 remained a lingering adherence to those antiquated usages which were 

 being supersetled in other concerns. Everyone knows that in whatever 

 manner bleaching is done, it must be effected by means of true chemical 

 agency ; and, therefore, it was to the chemist that the bleacher had, in the 

 first instance, to look for the discovery of more potent agents to effect his 

 object. The first great triumph in this department was the discovery, in 1798, 

 by Mr Tennant, of Glasgow, of a method of making saturated liquid chloride 

 of lime, — an article which was found to answer quite perfectly all the purposes 

 required by the bleacher. This invention, for which he took out a patent, con- 

 sisted in the substitution of lime for potash. His patent right was resisted by 

 the bleachers of Lancashire, and was set aside by the verdict of a jury. The 



