A study of the evolution of Kristian Birkeland's theories of cosmical physics is presented, with special reference to his laboratory gas-discharge experiments. It is found that his most important thoughts were molded from an intense cross-fertilization between laboratory experiments, geophysical observations and mathematical modelling. Occasionally, original ideas of fundamental importance in the cosmic context emerged from unexpected laboratory results. Possible implications for a sound cross-dikciplinary approach to modern plasma science are discussed.
Francis Hauksbee (1660–1713) is well known for his double-barrelled air-pump. However, the origin of this pump, and Hauksbee's background, are often described as a mystery. This text seeks to dispel the riddle. It is argued that Hauksbee's competence as an exceptional maker of air-pumps was developed between 1699 and 1703 as a result of his experiences with the construction, manufacturing and sale of cupping-glasses. His cupping utensils embodied a new design, where syringes were used to evacuate the glasses, instead of the traditional way by fire or mouth suction. These syringes, which in fact were small air-pumps, were perfected between 1699 and 1701. A larger syringe, introduced in 1701, served as a transition from the cupping-syringe to his first air-pump for use in natural philosophy. This syringe was described as a ‘combined engine’, which could serve as an air-pump, a condensing engine and a syringe for injecting air, wax or mercury into pathological specimens. Hauksbee's first air-pump was a single-barrelled model introduced in 1702, based on the combined engine. Its various features, such as easy and convenient leak-tightening, exact pressure measurements by an in-built barometer and an air-inlet function for readmission of air into the receiver, are discussed. Finally, it is shown that these activities gave Hauksbee the reputation of being an outstanding instrument-maker, years before the double-barrelled air-pump was in sight.
This paper examines the second generation of British air pumps, covering the period 1700-1750. The air pump originated in the 1650s and 1660s thanks to the work of Otto von Guericke in Magdeburg, Robert Boyle in Oxford and London, and Accademia del Cimento in Florence. While these first models were often seen as unreliable and temperamental, and available to a small group only, the next period saw the air pump transformed into a publicly accessible device for use in public and private demonstrations, in practical applications, as well as in the production of new knowledge. In England, the instrument maker Francis Hauksbee and his followers played a decisive role in this process, which was connected, among other things, to popular medicine, anatomy and health. In this period, pneumatics (the field of air pumps and air-pump practice) reached a state where the pump came to be regarded as an unproblematic tool; and where a vacuum' came to be thought of and handled as an object.
Francis Hauksbee was active in London between 1699 and 1713. During those years he built scientific instruments, gave public lectures on natural philosophy and worked as a curator of experiments for the Royal Society. His most celebrated instrument is the double-barrelled air pump, which represents the 'state of the art' of eighteenth-century vacuum technology in Britain. Based on original texts and an examination of extant pumps of this design, this article offers a description of the air pump and an account of some of the experiments performed with it. In addition, notes on existing Hauksbee pumps to be found in modern museums and collections are provided.
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