DISCOVERY 



147 



made from mineral salts are now sometimes formed 

 from vegetable substances much more transparent, e.g. 

 madder. The same applies to certain modern colours 

 with an aniline base. 



" Now, it is very evident that, in order to obtain a 

 good radiographic image of a picture, two things are 

 essential : 



" I. The transparency of the support and the priming. 



" 2. The relative opacity of the colours or at least 

 of certain of the colours employed in the contrasts 

 forming the image. 



" Precisely these conditions are found united in 

 ancient pictures. On the other hand, modern pictures 

 provided with a somewhat opaque priming covered with 

 colours often more transparent to the rays give much 

 less perfect images, which are often even almost 

 invisible." 



Dr. Cheron, whilst hesitating to draw hasty con- 

 clusions from his researches, went on to say that one 

 might, therefore, sometimes hope to discover through 

 radiography the age of a picture and consequently reveal 

 its authenticity. Another result, thanks to X rays, 

 was the power to show all the damage a work of art has 

 undergone down the ages, notwithstanding the most 

 skilful restoration. In fact, as ancient pictures are in 

 question, the priming and colours used for restoration 

 would be of a different manufacture and probably of a 

 different atomic weight, and would be reproduced on 

 the plate bj' veritable spots with a perfectly definite 

 shape, revealing ravages sometimes unsuspected. 



" Finally — and this is perhaps the most interesting 

 side of these researches," continues the Doctor," picture 

 radiography reserved very many surprises. To see a 

 picture by transparence is to know its history in part. 

 Apart from the fact that the artist himself may have 

 modified his work whilst painting it, the portions 

 ' faked ' or repainted, the additions made to it are 

 revealed to us ; without mentioning the various 

 unexpected discoveries of entire pictures under works 

 of later date." 



I have reason to believe that when Dr. Cheron wrote 

 these last words he had in mind the statement that, at 

 the time when David and the painters of the Classical 

 School were at the height of their popularity, some of 

 the canvases of Fragonard were regarded as of such 

 little artistic value that the artists of that School used 

 them for the production of their own works. What a 

 prospect, indeed, the radiography of pictures opens up 

 for us in that direction ! 



We will now turn our attention to the pictorial 

 demonstration of Dr. Cheron 's researches— a most 

 convincing demonstration if ever there was one. 



Figs. 4 and 5 display very clearly the contrast 

 between the radiograph of an ancient picture and the 

 picture itself. The " Vierge de. Stella" has clearly- 



defined outlines and the figures can be recognised. On 

 the other hand, it reveals, at the bottom of the picture, 

 restoration the extent of which was unsuspected. In 

 a modern picture, on the contrary, no image would be 

 visible, apart from those parts which alone are formed 

 of a colour sufficiently opaque to make a shadow 

 through the white lead priming covering the canvas. 



Figs. 6 and 7 are of special interest, since this picture 

 of a " Royal Child at Prayer," belonging to the French 

 School of the fifteenth centur\', is in the Musee du 

 Louvre, where it was onl\- recently radiographed. The 

 Curators of the gallery believed, in accordance with 

 statements made in certain documents, that the original 

 background of the picture was at some time or other 

 greatly damaged, and that about a century ago the 

 damages were masked by means of the uniform black 

 background now seen in the picture. This hypothesis 

 is wholly confirmed by the radiograph. Moreover, it 

 shows that the painter at first made the child's bow a 

 little too large and then corrected his error. 



Many photographs show how easy it is to unmask the 

 picture forger by means of radiography. One of the 

 pictures radiographed represented a little Flemish 

 scene with country folk dancing and playing musical 

 instruments. The radiograph was most curious, for 

 there was not a trace of figures (apart from the head of 

 one of them, faintly visible in the centre), but in their 

 place appeared two peacocks, two ducks, and two hens 

 \vith very clear outlines. Evidently the picture was 

 really two pictures, one over the other on the same 

 support, in this case a wood panel. The first picture, 

 that of the birds, was an ancient work, since there was 

 no opaque priming to destroy the clearness of the out- 

 lines ; the second — falsely attributed to Van Ostade — 

 was probably modern, since the colours, with the 

 exception of the whites, were almost uniformly trans- 

 parent to the rays. 



It should be said, in conclusion, that these results 

 have produced a profound impression in Parisian art 

 circles. M. Jean Guiffrey, the Curator of the Louvre, 

 finds them " most interesting." The well-known critic 

 M. Charles Henry saj'S : " There can be no doubt that 

 this method of examination is capable of furnishing 

 experts with new and precious elements " to enable 

 them to form an opinion. Whilst that excellent 

 publication Le Biilleiin de la Vie Artistique pronounces 

 the scientific value of Dr. Cheron 's work as undeniable. 

 Henceforth it ought to be impossible for any more 

 spurious " masterpieces " either to come into sale- 

 rooms or pass the Customs at the port of New York. 



Bibliolheca Chemico-Mathematica. A catalogue of works 

 in many tongues on exact and applied science. 

 Two vols. (Henry Sotheran & Co., 63s.) 

 To be reV'iewed ne.xt month. 



