56 



instead of a wandering and despised people, we 

 may see the whole Jewish nation repenting of 

 their former obduracy, and yielding up their 



unbelief to a full though tardy conviction." 



. 



24 th. We claimed my uncle's promise this 

 evening of describing the mode of polishing the 

 the glass. " When the grinding operation/' said 

 he, " has been completed on both sides of the 

 glass, it is again secured in plaster on a flat table, 

 and the surface is rubbed with a block of wood 

 covered with several folds of woollen cloth. 

 The workmen supply the cloth with polishing 

 powders, such as crocus, tripoli, and putty, 

 beginning with the coarsest, and changing gra- 

 dually to the finest." 



Wentworth observed that he had never seen 

 putty in a powdered state. 



"The putty of which you are thinking," my 

 uncle replied, " is a mixture of chalk, or whiting 

 with linseed oil, for the use of glaziers ; but the 

 putty to which I alluded is the oxide of tin. 

 Crocus is a preparation of the brown oxide of 

 iron ; and tripoli is a natural earth, which was 

 formerly imported from Tripoli in Africa, but is 

 now found in other countries. Both the 

 grinding and polishing of plate glass is per- 

 formed in the large manufactories by the steam- 

 engine." 



We begged of my uncle to describe to us the 



