A world-class archival achievement: the People’s Republic of China archivists’ success in opening the Ming-Qing central-government archives, 1949–1998

This article describes the first half century of the Communist government’s supervision and management of the central-government archives of the last two dynasties. Immediately with the Communist ascent to power in 1949, the new government took great interest in assembling and protecting the country’s archival documents, readying the Ming-Qing archives for access to scholars, and preparing for publication of selected materials. By the 1980s Beijing’s Number One Historical Archives, in charge of the largest holding of Ming-Qing documents, had become the first Chinese authority to complete a full sorting and preliminary catalogues for such a collection. Moreover, to facilitate searches, an attempt has recently begun to create a subject-heading system for these and other holdings in the country. In the first half century’s final decades, foreign researchers were admitted for the first time and tours and international exchanges began to take place.

An atmospheric dust recorder

An apparatus is described for recording general atmospheric dust. The full-scale range of the present model of approximately 120 × 10⁶ particles per cubic foot of air may be increased or decreased as desired. The dust concentrations measured are far below smoke concentrations. The method is to impinge dust on a slowly moving strip of transparent film, and to measure the deposit by a comparison of two beams of light, one passing through the dusty film, the other through clean film. The decrease in transmitted light due to the dust is balanced automatically by a motor-driven optical wedge in the unobstructed beam. The position of this wedge is recorded on a chart. Dusty air is sampled continuously for long periods. Rapid fluctuations of a few minutes in length are registered. In this, and in the fact that it is direct-reading, without tedious laboratory quantitation, the recorder offers distinct advantages over the present dust determinators, almost all of which take momentary samples. A different calibration is needed for different dusts. The machine may be adapted to laboratory or field use. In factories, auxiliary blowers may be operated through relays, when the dustiness exceeds a specified level.