102 M. Labillarditre on the Lillebonne Statue. [Aug. 



gold with it, of which there is no appearance below the surface 

 in the Lillebonne statue. It was, therefore, probably, gilded by 

 means of leaf gold, applied without the intervention of mercury, 

 as appears also to have been the case with the Corinthian 

 horses, which were for some time at Paris. 



" I conceive that it is not necessary to have recourse to the 

 intervention of the gilding to explain the cause of the oxidation 

 of the statue ; the presence of tin and lead appears to me to be 

 sufficient ; moreover, a metal completely gilded, does not form a 

 voltaic pile, since the circle is closed, and the metals are in 

 immediate contact. It is true that in the course of time solu- 

 tions of continuity may take place.* 



" An incipient oxidation at the surface was sufficient alone to 

 effect the oxidation of all the parts of the statue, provided it 

 were in a moist aerated ground. We often find in the earth 

 copper, which externally is in the state of peroxide, internally 

 in that of protoxide, and metallic in the centre. Iron also is 

 frequently seen peroxidated at the surface, and in the state of 

 protoxide in the interior. As soon as oxygen has seized on a 

 metal in a moist place, it is propagated successively towards the 

 interior, like, as it were, a gangrenous point, and is replaced by 

 that at the surface, as is particularly remarkable on iron ; the 

 moment a spot of rust is formed on it, it extends in all directions." 



To this abstract of M. Vauquelin's paper, we shall add a note 

 on the same subject addressed by M. Houtou Labillarditre to 

 the Editors of the Annales de Chimie. The subject receives 

 additional interest at the present moment from its analogy to the 

 important question that has for some time occupied the attention 

 of our illustrious countryman, and afforded him another oppor- 

 tunity of exalting the splendour of his own fame, and of benefit- 

 ing his country. Our readers will see in another part of this 

 number of the Annals the details of Sir Humphry Davy's expe- 

 riments on the means of preventing the action of sea water on 

 the copper sheeting of our ships, and the simple but sagacious 

 train of reasoning which led to their institution. We must 

 confess that M. Labillardiere's explanation of the oxidation of 

 the Lillebonne statue, is much more satisfactory to us than 

 M. Vauquelin's. Indeed that gentleman's hypothesis seems 

 irreconcileable to the fact ; for tin and lead being positive metals 

 with respect to copper, should rather prevent than promote its 

 oxidation. J. G. C. 



Note on the Lillebonne Statue. By M. Houtou Labillardiere, 

 Professor of Chemistry at Rouen. 



We cannot, with any probability, suppose that the ancients 



* M. Labillardiure ascribes the oxidation to the galvanic influence of the gilding. 



