Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Philipp Reis's telephone in Aberdeen   A telephone sender following the design of Johann Philipp Reis made by W
Ladd, London 1863, in the Natural Philosophy Collection of the University of
Aberdeen is illustrated and described. How Reis came to invent a telephone some
15 years before Graham Bell's patent is discussed, with 19th century
illustrations. The method employed by Reis is outlined and contemporary letters
by Reis are reproduced, including an extensive letter to the instrument maker
William Ladd. The origin of the Aberdeen instrument is given and some of the
reasons why Bell was granted his patent in spite of the existence of Reis's
instrument are suggested. The monument to Reis erected after his early death is
shown.

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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th