ENG-1962 — Page 215

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LAND AND HOUSING

the more developed parts of the New Territories is likely to decrease year by year. During the same period, land transactions in the New Territories brought in premia of $983,807 for sales by public auction and private treaty; $4,498,087 for land exchanges, and $486,524 for modifications of lease conditions. (Details of premia received on sales of Crown land between 1851 and 1960-1 are given in Appendix VIII).

Surveys. All surveys in Hong Kong are plotted on the Colony grid, which is a Cassini plane rectangular one with its origin on Victoria Peak. The grid meridian does not coincide with the true meridian at this point. The main triangulation, which is of a secondary standard, was observed in the 1920's and was adjusted by the War Office in 1928-30. Minor triangulation stations have been established over the years during the course of surveys in specific areas, and the horizontal control further extended by traversing. The urban area of Hong Kong Island, Kowloon and New Kowloon is surveyed at the large scale of 1/600 (50 feet to one inch). This is necessary because of the congested and crowded conditions in the built-up areas of the Colony. One hundred and fifty-two sheets of Hong Kong Island and 86 of Kowloon and New Kowloon are available in this series.

The New Territories remain largely rural, but the pressures of a rising population and an expanding economy have resulted in a striking growth of industry and housing. To meet this activity and to pinpoint individual land holdings a wide coverage of up- to-date survey sheets to a large scale is of first importance. To date, 331 sheets have been completed to a scale of 100 feet to an inch. These surveys form the basis for further scale plans required for planning, land records, and other purposes, and which are re-drawn from photographic reductions. In addition to supply- ing survey sheets of the Colony showing the plan position of buildings, the survey division of the Crown Lands and Survey Office is also responsible for establishing differences of level.

The first recorded levelling in the Colony was carried out in 1866 by HM surveying vessel Rifleman. For the purpose a datum was established roughly at the then mean sea level. To provide a permanent record, a copper bolt was driven into the wall of a storehouse in the Royal Naval Dockyard and its height above the assumed datum measured. Since then this sounding datum,