of a Wax from China. 379 



harder, more brittle, and of a more fibrous character of cry- 

 stallization. The melting-point of the wax is about 83° C. It is 

 but very slightly soluble in either alcohol or aether, but dissolves 

 with great facility in naphtha, out of which fluid it may be 

 crystallized. This substance is generally spoken of as a ve- 

 getable wax : on looking however into such facts as I can 

 gather which throw any light on its origin, it seems more than 

 probable that, like bees'-wax, it is the secretion of an insect. 

 Sir George Staunton, in his Embassy to China*, gives an 

 account of a wax of insect origin, which there formed an article 

 of trade, and in his work may be seen a drawing of the insect 

 and of the tree on which the insect lives. Other writers on 

 China give a similar account. In the Comptes Rendus for 

 1840 f is a paper by M. Stanislas Julien, who gives an account 

 of this tree wax, and states it to be the work of an insect: 

 where may be found also a great number of extracts from 

 Chinese writers on agriculture, giving an account of the insect 

 itself and of the trees suitable for its food ; one of these trees 

 is the Rhus succedancum. This same gentleman, M. Stanislas 

 Julien, gave to M. Lewy, who was engaged in an investigation 

 on these wax substances, a specimen of the wax from this very 

 plant, which is therefore in all probability this insect-wax. 

 The melting-point, the appearance and the analysis of this 

 wax, as given by M. Lewy, agree so exactly with those of the 

 wax which I have examined, that I cannot but believe them 

 to be the same chemical substance, and that this wax also is 

 of insect origin. 



The existence of any other wax-making insect, such as this 

 Coccus cerferus, besides the bee, is a point of considerable in- 

 terest in relation to the question as to the origin of the wax in 

 that insect, and the possibility of the chemical transformations 

 by which it is produced. 



The Chinese wax, as it appears in commerce, is a substance 

 nearly in a state of chemical purity. By alcohol small portions 

 of a greasy matter may be separated from it, and on distillation 

 it affords traces of acroleine, which is not a product of the 

 distillation of the pure wax. The impurities however are 

 unimportant. 



I have spoken of this substance as a wax ; and in truth, 

 although to the eye it more nearly resembles spermaceti or 

 stearine than ordinary bees'-wax, the substance, nevertheless, 



* Vol. i. p. 352, edition 1797. 



f Vol. x. p. 619. The title is " Nouveaux renseignements sur la cire 

 d'arbre, et sur les insectes qui la produisent." See also in the same volume, 

 M. Virey, Sur les insectes qui produisent la substance appelee par les Chinois, 

 " Cire d'arbre'" 



2 C2 



