The Malays also work jungle produce, of which the most important are gutta, rattans, agila wood, camphor wood, and the beautiful kamuning wood which is used by the natives for the hilts of their weapons.
Para-xylene is obtained when camphor is distilled with zinc chloride, but it is best prepared from para-brom-toluene or dibrombenzene, methyl iodide and sodium.
This work led naturally to the synthesis of many terpenes and members of the camphor group; also to the investigation of various alkaloids and natural colouring matters.
A curious fact, which may be used for the detection of the minutest quantity of oils and fats, is that camphor crushed between layers of paper without having been touched with the fingers rotates when thrown on clean water, the rotation ceasing immediately when a trace of oil or fat is added, such as introduced by touching the water with a needle which has been passed previously through the hair.
The motion of small pieces of camphor floating on water arises from the gradual solution of the camphor.
The camphor trade being a government monopoly, the quantity exported is under strict control.
In 1755 Menghini published an elaborate study of the action of camphor on a great variety of different kinds of animals.
If this takes place more rapidly on one side of the piece of camphor than on the other side, the surface-tension becomes weaker where there is most camphor in solution, and the lump, being pulled unequally by the surface-tensions, moves off in the direction of the strongest tension, namely, towards the side on which least camphor is dissolved.
Buchu leaves contain a volatile oil, which is of a dark yellow colour, and deposits a form of camphor on exposure to air, a liquid hydro-carbon being the solvent of the camphor within the oil-glands.
The thickness of the film of oil adequate to check the camphor movements can be determined with fair accuracy by depositing a weighed amount of oil (such as 8 mg.) upon the surface of water in a large bath.