Dating Historical Scientific Equipment

Catalogues of scientific equipment have been available in Great Britain since at least 1843, from specialised dealers.   Since these catalogues have diagrams or photographs of the equipment, it can be compared visually.   So these catalogues are a reference for dating.

Equipment offered from dealers by means of catalogues always carries the name of the maker or dealer.   These makers have an established date and when mergers have occured the dates of these mergers are recorded on the catalogues themselves together with the changed names of the new firms.   The following table traces the origins of important British firms since 1843 (source: Griffin & George catalogue of 1961; a short history).

1843     R. & J. Beck Ltd. (optical instruments only)

1848     John Joseph Griffin & Co.

1872     F. E. Becker & Co.

1881     Baird & Tatlock

pre 1897     W. & J. George Ltd.

1897     George & Becker Ltd.

1906     Standly Belcher & Mason Ltd.

1909     Gallenkamp & Co catalogue at Sir Temi Zammit Laboratory, Castellania

1928     Griffin & Tatlock

1944     (October) W. & J. George & Becker Ltd.

1954     Griffin & George Ltd.

1960     R. & J. Beck equipment offered through Griffin

So, reference to the manufacturer can give the date of manufacture of equipment within 15 years on average.   If catalogues are available the equipment can usually be traced to within 4 years of its manufacture.   Equipment without the name of the manufacturer could be one-off pieces and if not recent can be valuable pre-1843.

Examination of the items themselves will yield accurate estimates of the date of manufacture.   The constructional materials of the bulk of the item and special materials used can give good indications.

Solid brass on instrument bodies indicates pre 1900.   Brass sheet on instruments can indicate 1900-1950.   Of course, brass can be used as a traditional constructional material in later special equipment such as barometers and other meteorological instruments.

The insulators used in electrical equipment can give an indication of the date of manufacture as in the following table:

pre-1900     wood as insulator in low voltage equipment

from 1930   paraffin wax to insulate windings; also glass for high insulation in this period

about 1900  ebonite

          1920  bakelite (phenol formaldehyde)

          1940  polyethylene and other thermoplastics

          1960  newer thermosetting resins

          1970 co-polymers

pre-1900     glass domes

post-1900   glass fronts (glass sheet set in grooves to the present days)

plating on brass from 1950; chrome and nickel.

wood on older equipment was mahogany, other woods later

Insulation on wires    silk pre-1930

                                 cotton  1930-1950

                                 enamel 1950-modern

                                 shellac  1940-1960

                                 rubber  1940-1950

Other insulators         mica     1930

                           asbestos     1950

              moulded ceramic     1950 to 1970

                               PTFE     1970

                               PVC       1960

Raymond Libreri    31 January 1900