If the plants are subjected to some process, before mounting, by which injurious organisms are destroyed, such as exposure in a closed chamber to vapour of carbon bisulphide for some hours, the presence of pieces of camphor or naphthalene in the cabinet will be found a sufficient preservative.
Formula (4) is symmetrical and based on Kekule's formula: it is in full accord with the syntheses and decompositions of the naphthalene nucleus and the number of isomers found.
When, as in the formation of naphthalene tetrachloride, for example, the one ring becomes saturated, the other might be expected to assume the normal centric form and become relatively inactive.
The centric formula proposed by Bamberger represents naphthalene as formed by the fusion of two benzene rings, this indicates that it is a monocyclic composed of ten atoms of carbon.
As an example we may take the case of mixtures of naphthalene and 13-naphthol, substances which form solid solutions in each other.
NAPHTHYLAMINES, or Aminonaphthalenes, C10H7NH2, the naphthalene homologues of aniline, in contrast to which they may be prepared by heating the naphthols with ammoniazinc chloride.
One of the earliest red-hot tube syntheses of importance was the formation of naphthalene from a mixture of alcohol and ether vapours.
The former, based on Kekule's symbol for benzene, explains the decompositions and syntheses of the ring, but the character of naphthalene is not in keeping with the presence of five double linkages, although it is more readily acted upon than benzene is.
KOnigs, and the observation that anthraquinone yielded oxyanthraquinones when treated in the cold with strong sulphuric acid, and the recent introduction of fuming sulphuric acid for the oxidation of naphthalene to phthalic acid, a process of great value in the manufacture of artificial indigo, may be noted.
The higher the heat of carbonization the more naphthalene appears to be produced, and gas managers of to-day find the removal of naphthalene from the gas a difficult problem to solve.