Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The silver-plated mirrors of the Historical Collection of Physics
  Instruments of Palermo University   In the paper we will describe three instruments of particular historical and
didactic interest belonging to the Historical Collection of Physics Instruments
of Palermo University: a convex mirror most likely dating back to the early
nineteenth century and a pair of burning mirrors most likely dating back to the
mid-nineteenth century. After an introduction on the historical development of
mirrors and on their principle of operation, we will describe the
characteristics of the instruments of the collection and the interventions
carried out.

18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn