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trfXIV. On the Effects produced Ir/ the Use of the Oxy- 

 muriales of Lime and Magnesia in Bleaching. By Mr. 

 William Moore. 



To Mr. Tilloch. 



Sir, In the proceedings of the Kirwanian Society of 

 Dublin, published in your Magazine for last month, Dr. 

 Ogilby havins; stated some assertions he said were made 

 by Professor Davy, as to the theory and effects of oxymu- 

 riate of lime in bleaching; as I have been present at the 

 lectures when those assertions are said to have been made, 

 I am confident Dr. O.'s statements are incorrect; I there- 

 fore trouble you with the following narration of facts : 



Sir Humphry Davy, having stated that muriate of lime 

 had been proved by experiments to have a deleterious effect 

 on linen cloths, recommended the use of oxymuriate of 

 magnesia for that of lime in bleaching. His reasoning as 

 to the muriate of lime was, *' that bodies in their nascent 

 state acted with more energy than when they had been 

 formed ; and not as Dr. Ogilby says, that '* if a strong so- 

 lution of muriate of lime rendered cloth unsound, a weak 

 one ought to be proportionally detrimental." The Doctor's 

 experiments to prove that muriate of lime had not an in- 

 jurious action on linen cloths, I have repeated, viz. having 

 steeped cuttings of full bleached linen in solutions of the 

 neutral salt of different degrees of strength, some nearly 

 saturated : they were steeped* only for twenty-four hours ; 

 and upon being well washed and dried, they viere found to 

 be so rotten as not to require any longer trial. The re- 

 petition of Dr. Ogilby's experiments was "deemed woithy," 

 not from an idea " that Sir Humphry Davy'b views on this 

 subject were all together erroneous," as the Doctor modestly 

 asserts, but from a presumption that the Doctor m>gfit 

 possibly be mistaken. 



Dr. Ogilby also contradicts an assertion which he says 

 Sir Humphry Davy made; namely, " that magnesia had 

 entirely superseded the use of lime in Ireland for bleach- 

 ing ;" and the Doctor says, that not a single bleacher uses 

 it. To refute this, I need only state (as nearly as possible) 

 the words made use of by the Professor in the lectures. 

 He said that he was happy to state that some hints which 

 he had the pleasure to give in a preceding course of 



* The Doctor repealed the immersions four times, for twenty-four hours 

 each tiaie. " ~ 



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