2 Thorpe and Simmonds, Lead Fritts. 



ness of the lead glazes used by potters may be judged. 

 The standard proposed is that the " solubility " of the 

 glaze as regards lead, determined under the conditions 

 described in the foot-note (p. i), shall not be greater than 

 two per cent. This limit is based upon a study of the 

 quantity of lead yielded to dilute acid under the specified 

 conditions by a number of lead fritts used in pottery 

 manufacture both at home and abroad. 



Practical Bearing. — So far as the practical aspect of 

 this question is concerned, the reply to Messrs. Jackson 

 and Rich's contention is obvious. Suppose that workable 

 glazes can be obtained, which, when ground to the degree 

 of fineness necessary in practice, are within the selected 

 limit of solubility. Then it is of no consequence that 

 their solubility is smaller when the glazes are more 

 coarsely ground. This is all that is involved in the point 

 under discussion. 



Now, as a matter of fact, such glazes are in use. This 

 is shown by the list given in certain Reports to the Home 

 Secretary on the " Use of Lead in the Manufacture of 

 Pottery" (Parliamentary paper No. Cd. 527, p. 10), which 

 shows the solubility of the lead in a number of glazes 

 together with the statements of the manufacturers regard- 

 ing the degree of fineness in each case. 



It is true that this list may possibly not include 

 examples of the most finely ground glazes ever employed 

 by the potter, though it may do so. But it certainly 

 includes some which are in at least an average condition 

 of fineness ; and the difference between these and the 

 most finely ground glazes can be but small. 



Influence oj fineness a subot-dinate matter only. — As 

 regards the more theoretical aspect of the matter, it is in 

 the first place quite easy to show that the solubility of the 

 lead in fritts does not depend merely, or even largely, 



