564 REPORT — 1880. 



wash a certain weight of powder. From the answers received, it was ascertained 

 that no general rule was followed, everyone doing what he considered best for his 

 purpose ; but it was considered probable that the damage to fabrics noticed by 

 Persoz arose from minute particles of unwashed, or imperfectly washed, bleaching 

 powder finding their way into the interstices of the fabrics, which aftei-wards had 

 been so imperfectly washed that when they were passed through the acid bath an 

 energetic bleaching agent was evolved, and so the fabric was destroyed. To deter- 

 mine whether this was likely to be the case, bleaching powder was dissolved, and 

 the residue washed in the manner adopted at one of the largest greens in Ireland ; 

 and in the residue thus prepared, pieces of linen and cotton were steeped for twentj'- 

 four hours, after which they were found to be stiU sound, but decidedly altered in 

 colour, and after being passed through an acid bath, both samples were of that 

 shade of colour known in the trade as a ' low cream.' 



On washing bleaching powder according to the manner adopted at several 

 greens, and then estimating the chlorine remaining in the residues, it was found to 

 vary from -2 per cent, to 7 per cent. ; and from these figiu-es and the above experi- 

 ments there can be no doubt but that the damage, if any, arises, not from a basic 

 chlorate, but from a number of infinitesimal particles of 'the undissolved bleaching 

 powder becoming lodged in the interstices of the fabrics ; and, of course, those parts 

 where they were lodged would require a great deal more washing than the remain- 

 ing portions of the fabric ; and if, either by carelessness or any other cause, the goods 

 happened to be imperfectly washed, then, when soured, they would not unlikely be 

 damaged in the parts containing the undissolved particles by the evolved gas, while 

 the remaining portions would be imaltered. 



In conclusion, I must take this opportunity of thanking Professor Lunge, under 

 whose supervision these experiments were carried out, for the many valuable sug- 

 gestions which he was kind enough from time to time to make. 



