188 Agricultural jiuseum 



{^0, fem-ove its rongliness, the whole piece is made to 

 'pass rather slowly over a red hot iron cylinder, and in 

 abs9ii;te contact with it ; and during the whole operation, 

 i, the iron is ipaintained at a red heat, by the aid of a fur- 

 nace. 1 wol^ld not assert a thing seemingly so incredi- 

 ble, had I not witnessed the process ; and my astonish- 

 inent was not less tlian your incredulity will be, pro- 

 vided the fact be new to you. This operation is not con- 

 ^iined to the velvets. Most of the cotton goods arc siut; 

 ", €d in the same manner, to smooth them for the linaL 

 finishing; and they assured mc, (what imleed appears, 

 scarcely credible) that the finest muslins wore treated 

 in the same way. 



The new process of bleaching is now extensively in- 

 troduced at Manchester, and has, I believe, nearly sub- 

 verted the old. The bleaching w hich used to occupy 

 months, is now performed in a few days. 



Manganese, sulphuric acid, water and common salt., 

 are placed in large leaden stills, heated by steam. A 

 Very suffocating and corrosive gas § rises, which is made 

 to pass into water, having abundance of lime suspended 

 in it ; the lime condenses the gas, and produces with it 

 the bleaching drug, into a solution of which the goods are 

 plunged, and it is wonderful with what rapidity the co 

 lour is discharged. Some weak acid is usually added to 

 liberate the bleaching prineij)le. This method of bleach- 

 ing is a discovery of modern chymistry ; and when you 

 consider that all the coloured cotton stuffs must be first 

 bleached before they can be dyed, you will sftc at once 

 the great importance of the discovery. 'I'he saving is in 

 time, for the materials are more coi^tlj' than those eni- 

 ployed in the old wa}'. 



A great deal of American Sumac is used hcTc in i\\- 

 ing. 1 learned in one of the dye-houses, that the .'^mcii- 

 cans give themselves unnecessary (rouble in grindin'ff- 



