An EJJizj> on Bleaching. 259 



trifles, ranged as in an aquafortis manufactory, the tubes of 

 which are conveyed into a chamber containing concentrating 

 tubs. His apparatus for the bleaching of paper is very in- 

 genious, and deferves to be defcribed. In the laft place, 

 others have arranged five or fix large ca(ks, like Wolf's ap- 

 paratus, in fuch a manner as to make each cafk perform the 

 functions of a tubulated flaik. The bleachers in Ireland em- 

 ploy a kind of leaden alembic capable of containing forty 

 gallons of water ; a capacity more than fufficient to contain 

 the charge, and to favour the fvvelling which takes place by 

 the reciprocal action of the matters during the diftillation. 

 This alembic, (fee Plate IV.) of a conical form, and having 

 a very broad bafe, refts in a balneum marise, in order that it 

 mav be fubje&ed to a progreflive heat ; and the neck is of 

 fuch a height, that any fulphuric acid which happens to 

 rife may fall back. The cover is perforated to afford a paf- 

 fage to the handle of an agitator, which ferves to (iir the 

 matters at the bottom of the alembic : this agitator is of iron 

 as well as its arms ; but the iron is covered with a pretty 

 thick plate of lead, that the acid may not attack it : the 

 handle goes through a leather collar, to prevent the efcape of 

 the gas; The fulphuric acid, diluted with water, is intro- 

 duced into the leaden apparatus by means of a fmall glafs or 

 leaden funnel, the tube of which is bent to guard againft the 

 reaction of the gas. The apparatus is alfo furniflied with a 

 condenfer, into which the gas is made to pafs. This vefiel 

 has feveral (helves and ar^ agitator. The latter goes through 

 a leather collar in the top of the condenfer, paffes down 

 through the (helves, and is furniflied with arms between 

 each of the (helves ; by which means the gas in its afcent is 

 cxpofed to the action of the liquid 111 a ftate of great agita- 

 tion, and has a long way to travel through it. (See the Plate.) 

 I (hall now fpeak of an apparatus which, in my opinion, 

 is free from th'ofe faults which generally attend an apparatus 

 of lead, which always becomes oxidated, and is at length de- 

 ftroyed. This apparatus * conflfts of a feries of conical ma- 

 traflcs with long necks, furnilhed with bent funnels as well as 

 tubes, both of.glafs, which are conveyed into a common refer- 

 voir. This reiervoir ought to be perforated in fuch a manner 

 as to leave room for the introduction of a tube of a larger (ize 

 (two inches) communicating with the (irft condenfing calk 

 or cylinder, made of white wood, twenty inches in diameter, 

 bound round by hoops made tight with fcrews, and com- 

 pletely water proof. Care muft be taken to cover thefe hoops 



* See Plate II. fig 1 and 2, given in our laft Number; and the de- 

 scription, page 101 and ill, 



R % with 



