J7S farmers' and mechanics' journal. 



ment may be required to have more or less relief. When the coF' 

 rosion is completed, the varnish or wax must be removed with 

 spirits of turpentine, which may be applied with a bit of sponge, 

 and then be wiped off with soft rags. 



The article, being made quite clean, is now rubbed over with a 

 soft brush, dipped into finely-powdered plaster of Paris, and is ap- 

 plied in the dry state. This powder fills the pores of the corrod- 

 ed parts, giving a certain degree of opacity, similar to that which 

 is left from the tools of the sculptor. It forms a good ground that 

 contrasts well with the ornament, and makes it appear with great- 

 er advantage than if left merely in the corroded state. 



The alabaster of which the vase is made, was procured from a 

 quarry at Chellaston, about four miles from Derby. 



To clean Alabaster Sculptures. 



Spots of grease are first to be removed with spirits of turpen- 

 tine ; the article is then immersed in water, where it is suffered to 

 remain about ten minutes, or, perhaps, a little longer, if the thing 

 be very dirty ; it is then rubbed over with a painter's brush, suf- 

 fered to dry, and then treated with plaster of Paris as above, when 

 the article will be found perfectly clean, as if just from the hands 

 of the sculptor. 



A piece of sculpture that would take several days to clean by 

 the usual way, vvith fish-skin and Dutch rushes, is, by this process, 

 completed in half an hour. \Journ. of Arts , ire. 



MOULD FOR MAKING CORES USED IN CASTINGS. 



Sir, — In making some kinds of castings, it is highly important to 

 secure apertures of uniform calibre through them ; but this object 

 is seldom obtained, owing to the difficulty of forming accurate cores. 

 The above diagram represents a mould proposed by Mr. Isaiah 

 LuKENS, of Philadelphia, by which this difficulty may be effectual- 

 ly obviated. Should you think its publication likely to subserve 

 the interests of the highly useful class of our citizens, who are en- 

 gaged in the iron and brass foundry business, you will please give 

 it a place in your Magazine. 



