|(J STUCCO FOR PRESERVING STONE. 



be used after it had grown dry, though less advantageously 

 than when fresh made and well drained. 



3. A mixture of this cheese with lime simply forms a 

 paste, that adheres but slightly even to coarse grained stone, 

 and not at all to paper. 



4. Calcined gypsum, which in a small dose facilitates the 

 uoion of the lime and cheese, renders the paste hard and 

 clotty, if it be used in too larj^e proportion. 



5. It had appeared, that whitinjij, which is used in paper 

 , hangings, might be admitted into the preparation: but it 



was found, that, if this earthy substance, which in a pro- 

 cess described by Mr. d'Arcet is carried to twenty times the 

 weight of the lime, may be used with success for inside 

 work, it would make too thick a coat, and would not adhere 

 so strongly to the stone. 



6. The addition of a very little ochre, or red oxide of iron, 

 to this preparation, will give it such a tint as may be wished, 

 without altering its properties. 



Proportioaof The proportion of cheese must depend in some measure 

 cheese. on the state in which it is, and cannot be determined pre- 



cisely but by the condition of making a soft paste. A fourth 

 of the weight of the solid matters appears to be a sufficient 

 quantity of cheese fresh from the press. 

 Preparation of The quantity of lime to be used at once being deter- 

 tkecompound. mniea on, it is to be slaked in as little water as possible, but 

 enough to make it pass through a sieve not very fine, in or- 

 der to separate the parts that will not slake. This is to be 

 triturated with the cheese to the consistence of a soft, 

 smooth, and coherent paste. To this are to be added the 

 calcined gypsum and the white lead, which must not be 

 adulterated with chalk, and by farther grinding on the stone 

 with a little water the whole is to be reduced tp a pap, rather 

 thick than fluid. Lastly it is to be diluted with common 

 water the moment of using it, which is to be done with a 

 painter's or varnisber's brush. 



«' IV. 



