272 Mr. Delaval oh the Caiije of the 



bur, it is vinqueftionable that a icientific knovy- 

 Icdge of the nature of the colours, which they 

 ufed, would have enabled even the greateft maf- 

 ters to have communicated, to thufe works, a 

 ftill higher degree of excellence. 



1 {hall not regret the labours which I have 

 beftowed on the fuhjeifl of thek page?, if they 

 contribute to the advancement of thofe ufeful and 

 elegant arts, which are of much importance to a 

 commercial nation; or if, by the difclofure of 

 phyfical truths, they extend the bounds of fci- 

 ence, or open new paths to its improvement. 



the true principles of optics, and of their art. One of 

 our moll eminent painters has obferved, from a minute 

 and accurate examination of fome of the moft capital 

 piftures of Titian, Tintorec, Paul Veronefe, and other 

 Italian, Flemifh, j|nd Dutch mailers, that they painted 

 with tranfparent colours, upon a white ground. This 

 praftice was carried to the highcll degree of perfeilion 

 by Correggio. That great colourift grounded his pictures 

 with black and white only: and by the delicacy, clear- 

 nefs, and brilliancy of the tranfpnrcnt colours, which he laid 

 on the grounds thus prepared, he gave to his compofitioni 

 a peculiar force and relief, and a near refemblance of 

 nature. Few modetn artifts have been able to comprehend 

 the means, by which thofe efleds were produced. Leo- 

 nardo Da Vinci, in his inllrudive Treatife of Painting, 

 recommends the ufe of white grounds, and tranfparent 

 colours, as the true method of procuring the moll brilliant 

 colouring. Cap. 100. " Sempre z. quelli colori, che 

 " vuoi che habibno bellezza, prepararai prima il campo 

 *' candidifTimo, e quefto dico de' colori che fono tranfpa- 

 " renti, perche a quelli che non fono tranfpareati, noa 

 " giova campo chiaro." 



ExPERI- 



