140 SCIENTIFIC NEWS. 



Manner of ufmg 3d. Wheg thefe two materials are to be ufed, the ferum iV 



it, &c. fi r ft poured into a wooden or earthen vefTel, and mixed with 



a fufficient quantity of the lime, pulverized as directed above, 



taking care to preferve the mixture of a proper fluidity to be 



eafily Ipread with the brum over the furfaces to be covered. 



4th. Too great a quantity of this paint mull not be prepared 

 at once, becaufe it thickens very faft, and when it has acquired 

 too much confidence it cannot be ufed. This inconvenience 

 may, however, -be remedied by keeping the fluidity at the 

 fame point, by the addition of a fufficient quantity of ferum, 

 which fhould always be kept in a veifel near that containing 

 the paint, that it may be ufed when neceflary. 

 Addition of co- 5th. The colour fo prepared, fhould be ufed as quickly as 

 lour. poffible. 



General re- 6th. As the colour refulting from the application of this pre- 



roarks. paration is always white, and as there are circumftances in 



which a different colour is wifhed for, this may be obtained, 

 by adding a bolar earth of a red, black, green, or yellow fpe- 

 cies to the ferum, at the fame time as the lime is mixed. Even 

 a beautiful blue may be obtained by ufing the blue glafs pre- 

 pared from oxide of cobalt, provided it be reduced to an im- 

 palpable powder. 



7 th. The ftrength of the compofition being neceflarily lef- 

 fened by the addition of the bolar colouring matters, the fame 

 degree of folidity may be preferved by adding to the ferum 

 ufed for diluting this compofition, a few whites of eggs ; but 

 particular care mufi be taken not to put too many, otherwife 

 the paint will be fubjecl; to fcale off. 



8th. This paint can only be applied on wood-work or coat- 

 ings of plafter, which have not been previoufly covered with 

 oil-paint. 



9th. As one layer will not be fufficient, two or three may 

 be laid on thofe furfaces which are required to be well painted ; 

 but before laying on a fecond coat, that which has been al- 

 ready applied mull be perfectly dry. 



lQlh. A beautiful polilh may be given to this paint by fric- 

 tion, in the fame manner as to other forts of paint ; it need 

 only be obferved, that it is better to greafe the cloths ufed for 

 rubbing it, with clear whale oil, rather than with any other 

 kind of oil. 



11th. To 



