Manchester Memoirs, Vol. xlv. (1900), No. 1. 7 



finds the symptoms have disappeared. Further, if the 

 certifying surgeon is of opinion that any of these workers 

 are constitutionally unfit to follow such employment 

 without running grave risks, he can interdict their further 

 employment in the lead processes. 



These two sets of safeguards, the mechanical and the 

 medical, have been now pretty generally adopted in all 

 pottery works in this country, under special rules from the 

 Home Office. The question of credit for the adoption of 

 these rules does not concern us here, though there is a 

 great deal more due to the manufacturers than is generally 

 supposed. That they have been of very great Jlsrvice is 

 shewn by the fact that although they have not been in 

 operation yet for quite two years, the number of plumbic 

 cases, due to the pottery industry, during the year 1900, 

 will be fewer by nearly one-half than they were in 

 1898. 



Quite recently a third and most important precau- 

 tion has been proposed by Dr. Thorpe, as an outcome of 

 the investigations he has conducted on behalf of the Home 

 Office during the last two years. Dr. Thorpe points out 

 that it has been found possible by certain manufacturers, 

 •especially on the Continent, to reduce the lead used in 

 their glazes to a form in which it is far less readily 

 attacked by dilute hydrochloric acid (and presumably 

 also by the gastric juice), than the white lead or red lead 

 in general use in this country. This result is attained by 

 first of all fusing the lead oxide necessary, along with 

 some siliceous and aluminous substances, so as to make 

 a lead glass, known technically as " fritted lead." * Much 

 depends on the chemical composition of the fritt, and on 

 its perfect preparation, but it is possible, with care, to 

 make fritted lead compounds which yield up to dilute 

 • Samples were shewn of a number of these substances. 



