Fiveand six-membered rings are the most stable and important, the last-named group resulting from the polymerization of many substances; threeand four-membered rings are formed with difficulty, and are easily ruptured; rings containing seven or more members are generally unstable, and are relatively little known.
True ring systems, which possess the characters of organic nuclei, do not come into existence in threeand four-membered rings, their first appearance being in penta-atomic rings.
Six-membered ring systems can be referred back, in a manner similar to the above, to pyrone, penthiophene and pyridine, the substances containing a ring of five carbon atoms, and an oxygen, sulphur and nitrogen atom respectively.
Proceeding to the six-membered hetero-atomic rings, the benzo-, dibenzoand naphtho-derivatives are frequently of great commercial and scientific importance.
The House of Assembly consists (as originally constituted) of 121 members, elected by single-membered constituencies, each constituency containing as nearly as possible the same number of voters.
Among the other decisions of the convention were: the choice of Pretoria as the seat of administration anti of Cape Town as the seat of the legislature, the renaming the Orange River Colony, Orange Free State Province; the provision of three membered constituencies and of proportional representation and the safe-guarding of the smaller communities by giving Natal and the Orange River colonies more members of parliament than they were entitled to on the voters basis.
The draft act, with its " one vote one value " principle, its three-membered constituencies and its scheme for proportional representation, threatened Dutch supremacy in the rural districts, and aroused the opposition of Hofmeyr, who secured the passage of amendments through the Cape parliament which destroyed the principle of equal rights.
Through the firmness of the Transvaal delegates, supported by the Progressives, the principle of equal rights was retained; the concession made to the Cape was the abandonment of proportional representation, while one-membered constituencies were substituted for three-membered constituencies.