School of Historical and Philosophical Studies - Theses
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ItemThe role of symbols in the development of chemistry to 1916 : with, A dictionary of chemical terms (1600-1800)( 1966)The Oxford English Dictionary offers a number of meanings for the word symbol; "Something that stands for, represents, or denotes something else (not by exact resemblance, but by vague suggestion, or by some accidental or conventional relation).... a material object representing or taken to represent something immaterial or abstract ...... a written character or mark used to represent something: a letter, figure or sign conventionally standing for some object, process." When chemistry is taught today it is presented with its symbols developed and the rules of their combinations defined. However, in reaching this stage the chemist's symbols at various times have had the meanings listed above. Chemists and historians of chemistry have discussed the roles and origins of symbols only to a very limited extent. The aim if this thesis is to provide a chronological review of the use of chemical symbols beginning with the exoteric alchemical symbols and concluding with electron theory bonds. We shall show how this use varied from the time when empirical shorthand characters were employed to the time when formulae or combinations of symbols were used as structural diagrams of molecules written in conformity with rules provided by a theory of composition. This association of formulae and rules for their construction will be examined against the often uncertain and disputed nineteenth century background of atoms, radicals and valence. I shall include in this background two examples of mathematical interests in formulae, which have been almost completely ignored by historians of chemistry. They are Bridle's calculus and Sylvester's quantities.
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ItemJohn Ridley's contributions to Australian technology and to the early progress of South Australia( 1979)This study is primarily concerned with the working career of John Ridley (1806-1887), and with his contributions to the flour-milling industry of South Australia, to wheat harvesting technology, and to the progress of the colony generally. Ridley emigrated to South Australia from the north of England in 1840, and remained there until early 1853. Although still a relatively young man, he then returned to England to live in semi-retirement. The following text will show that Ridley contributed substantially to the technical and economic progress of the young- colony in at least two separate ways :- (i) He built the first flour-mill in South Australia in the year 1840, and subsequently operated it as a very successful business until he left the colony in 1853. The mill was steam-driven, of substantial capacity for the time, and of considerable economic significance to the colony. The local flour-milling industry which grew up soon afterwards freed the colony from crippling expenditures for imported flour and other breadstuffs, thus permitting a sound local economy to be developed. During 1842 Ridley leased a second (inoperative) flourmill near Adelaide, completely refitted it, and brought it too into successful operation. As well as helping to alleviate the financial difficulties of the colony at the time, these two mills provided a timely stimulus to local wheat growing. Ridley exerted a considerable influence upon the early development of South Australia's flour-milling industry, by virtue of the high standards for efficiency, operating reliability, and sound profitability he established in his own businesses. The competitors he attracted were forced to achieve similarly high standards in order to survive. His work was thus of importance in helping to secure a sound base for the future growth of the industry. (ii) In late-1843 Ridley invented, constructed, and demonstrated a unique mechanical harvester for gathering grain crops. This machine, later known as the "Ridley Reaper" or the "South Australian Stripper", was subsequently manufactured and used in thousands within the colony. For more than half a century the machine played a major part in stimulating wheat production in the region by providing the simplest and cheapest harvesting method in the world at that time. Ridley's invention embodied a principle of operation which was entirely novel at the time it was introduced. In the late-nineteenth and early-twentieth centuries this same principle was incorporated into the designs of many other widely used grain harvesters. Ridley's machine therefore occupies an important place in the evolution of modern grain-harvesting machinery. The first two machines (both built by Ridley) were directly responsible for averting a serious harvesting crisis in South Australia at the 1843-44 season. Afterwards, when ever-increasing numbers of the machines went into service, a dramatic expansion of the colony's wheat-growing industry became possible. This in turn led to the development of a large export trade in wheat, and thus to an enviable economic prosperity for the colony. Whilst there is unanimous agreement that Ridley constructed and demonstrated the first successful machine of the "Stripper" type, his claim to have also invented the principle of its operation has been disputed. John Wrathall Full, another. pioneer South Australian settler, insisted that he and not Ridley originated the fundamental principle. In fact, he directly accused Ridley of stealing his idea and putting it into practice. The resulting controversy is examined in detail, and Bull's claim shown to be falsely based. Two further points of historical interest are also made and substantiated. Firstly, the "Stripper" was the first ever harvesting machine to successfully combine the operations of gathering and threshing the grain. And secondly, Ridley's "Stripper" was the first machine in the world to substantially displace hand-methods of cereal harvesting in its region. In the light of all the above considerations, it is suggested that Ridley's machine has not received either fair or sufficient notice in the histories of agricultural technology published to date. John Ridley's importance in the story of the development of mechanical harvesting has thus been unjustly neglected.