140 



weighing 50lb. of a five year and nine months old tree of average 

 growth, the leaves (271b.) and branches (231b.) being distilled 

 separately, the former yielding 767 per cent, of pure camphor and 

 some oil, the latter only traces of oil, showing that the whole of 

 the camphor is practically in the leaves and not in the yomig 

 wood. The reason of this should be investigated, as it is from 

 old wood that the bulk of the camphor of commerce is obtained. 



CHARACTERS. 

 The camphor obtained from all the above experiments has the 

 usual crystalline form, and is perfectly colourless unless 

 condensed in an iron vessel, when it is tinged with red from 

 the o.xidized iron. It floats on water, in which it is almost 

 insoluble, and small fragments rotate rapidly when floated 

 on this liquid. It burns with a yellow smoky flame, leav- 

 ing no residue, and volatilizes readily at the ordinary temperature. 

 It is easily soluble in alcohol, ether, and chloroform, and is preci- 

 pitated from the former in white fiocculent masses, when the solu- 

 tion is poured into water. It sublimes readily, and has an odour 

 of camphor, but not so powerful as ordinary camphor from old 

 wood. Its specific gravity is 987; it melts at 175° C, (347° F.) 

 and boils at 205° C. (400' F.). It dissolves readily in nitric acid, 

 with some development of heat, and immediate separation of the 

 solution into two layers, the upper of a red colour and the lower 

 pale yellow or colourless. The addition of water precipitates the 

 camphor as a white mass from the upper layer of the solution ap- 

 parently unchanged. 



SUBLIMATION EXPERIMENTS. 



These were conducted at varying temperatures and under 

 different conditions in order to try and obtainthe translucent state 

 common to commercial camphor. The most successful method 

 was by mixing the crude camphor with slaked lime in the pro p 

 tion of 40 to I, and subjecting this in a closed vessel to a low heat 

 for twelve hours, the heat being gradually increased up the sides 

 of the vessel in order to drive all the camphor into the upper por- 

 tion. Copper vessels are the best for the purpose, as glass is liable 

 to fracture from condensed moisture running down to the heated 

 sides. 



Before sublimation can be effected it is essential that all the 

 camphor oil should be expressed from the camphor. The cam- 

 phor when first distilled appears to be practically free from oil, 

 but after standing some days oil gradually separates and sinks to 

 the bottom of the mass of crystals, and this appears to continue for 

 months. Filtration with the aid of a vacuum effects a partial 

 separation, but in practice on a large scale it would be best 

 effected by means of a centrifugal machine similar to that employed 

 for the separation of crystalline sugar from molasses. 



OIL. 



The oil obtained with the camphor from the leaves is of a clear 

 yellow colour, having a specific gravity at 80' F. of "9662. It con- 



