xxviii Proceedings. [May 28th, igor. 



Ordinary Meeting. May 28th, 1901. 

 Horace Lamb, M.A., LL.D., F.R.S., Vice-President, in the Chair. 



The thanks of the members were voted to the donors of the 

 books upon the table. 



A paper on "The Influence of Grinding upon the 

 Solubility of the Lead in Lead Fritts," by T. E. Thoupe, 

 C.B., LL.D., F.R.S., and Charles Simmonds, B.Sc, was, in 

 in the absence of the authors, read by the Secretary. 



The paper is printed in full in the Memoirs. 



.After the reading of the paper, 



Mr. Burton pointed out that, even if grinding be pro- 

 ductive of variations in solubility of only about 50 per cent, 

 of its amount, a fritt not far within any fixed standard 

 limit would be dangerous or safe according to the fineness 

 of its grinding. He denied that the more soluble fritts are 

 the softer, stating that the contrary is the fact. He further 

 referred to the danger of lead-poisoning from inhaled lead dust, 

 a matter in which the imposition of a standard of solubility 

 of the substance affords no safeguard. 



Mr. Jackson stated that the finer portions of the fritts dealt 

 with by himself and Mr. Rich contained not more, but less, lead 

 oxide than the coarser portions. He liad himself determined the 

 solubility of different grindings of the same fritt, a fritt which was 

 passed as within the Home Office standard, at amounts varying 

 from below 2 per cent, to about 5 per cent. He exhibited some 

 photographs showing the result of the action of hydrofluoric acid 

 on glasses, which displayed crystalline forms suggestive of 

 distinct heterogeneity, even in the clearest glass. He protested 

 that he had not treated the fritts as single chemical substances. 



Professor DixoN and others joined in the discussion. 



