344 PdJniing with the Serum or watery Part of the Blood. 



thing will be neceflary but to mix a little white of an egg 

 with" the ferum before ii is united with the lime or the black 

 earth. I nuill here add, that wood painted in this manner 

 may be polilhcd, and made to acquire a certain degree of 

 luitre. In this cale I have obferved that fre(h fpermaceti 

 may be fiibftituted with advantage for the tallow or oil in 

 which the rags employed for rubbing wood before it is po- 

 lifhed are commonly dipped. This kind of paint mav be 

 applied aUo with the fame fuccefs to earthen ware, lead, iron, 

 cut ftone, &c. 



The circumftances which induced me to employ this new 

 kind of painting, obliged me to make an extenfive ufe of it, 

 without allowing me time to carry my operations any further. 

 More than 300 arrobes * of ferum were confumed in the 

 courfe of a few days. In this manner we were able to paint 

 not only the pafflige and bridse of the king's palace, but alfo 

 the windows and doors of tlie fame edifice, thofe of the 

 magnificent building of the Exchange, the Place de Taureau, 

 and many private houfcs. The happy efi'etts it produced, 

 when expofed to the eyes of the public, are a fufficient proof 

 that practice here perfeiSlly correfponds with theory. 



It is hardly necelTary to obferve, that the furfaces to be 

 painted muft be fmoolh ; that the wood muft be covered 

 with a llratum of plalter; and that this painting muft not be 

 applied over painting with oil or with turpentine, becaufe the 

 heat would make it crack. 



I propofe to continue the fmall number of trials I have al- 

 ready made, to render the ufe of my difcovcrv more general. 

 The following is the refult of thofe which I have hitherto 

 been able to attempt. 



In confequence of the vifcidity, adhefion, and fpeedy de- 

 ficcation of this compofition, it may be employed in the fame 

 manner as bitumen, to cement with great folidity broken ar- 

 ticles of every kind. In this cafe it oppofes a ilrong refift- 

 ance to the aAion of fire, water, many of the gafes, and to 

 vapour. 



As ferum contains a large quantity of albuminous matter, 

 having myfelf feparated from it nearly half its weight, it 

 may be employed with advantage for clarifying fugar, wine, 

 and other fubftances, in a more ceconomical manner than by 

 the white of an egg. 



This new compofition mav be employed alfo for covering 

 the furface of damp walls intended to be painted in oil co.- 

 lours; taking care, however, to cover it with a coaling of 



•* An arrobc weighs 25 or 26 I'ounds. 



plafler 



I 



