How to look for records of... Intellectual property: patents of invention

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1. Why use this guide?

Use this guide for advice on how to find patents of invention, and related records, dating from between 1617 and October 1852 and now held at The National Archives. There is also advice on records dating from as early as the 16th century relating to patenting of inventions.

Up to October 1852 the Court of Chancery was responsible for safe-guarding intellectual property rights in England and Wales, issuing and recording patents of invention and the related records.  The Patent Office took over this responsibility when it was founded in 1852. Today it is the responsibility of the Intellectual Property Office.

We hold the records of the Court of Chancery here at The National Archives but for patents from 1852 onwards, contact the Business and IP Centre at the British Library. The Espacenet database contains information about patents worldwide from 1836 to the present day.

Consult our guide to registered designs for advice on other records of inventions.

2. The patenting process and the records it produced

Inventors can get an exclusive right to manufacture their own inventions for a limited period. The state issues ‘letters patent of invention’ and enrols them to record this right. Initially, in the years from 1617, the inventions were enrolled but not described in much detail. Later in the century they came to be described in increasing detail until this became routine. From 1711, specifications (providing full working details of the invention) began to be enrolled in a different place, after the issue of the patent. By 1734, they were almost compulsory. Read more about historical British patents on the British Library website.

2.1 Patents of inventions

The patent itself contains the formulaic text for the application of patents of invention. It was enrolled on parchment.

2.2 Specifications of inventions

The specifications of inventions contain illustrations and information about the inventions themselves. They were also enrolled.

Printed copies of these specifications, where they exist, were created in the 1850s following reforms to patent law. Where there were no specifications, the details of the grant recorded in the Patent Rolls were transcribed.  These printed specifications and transcriptions are held by the British Library.

3. Finding patents of invention 1617-October 1852

Step 1: Find an entry in the published indexes

The first stage in finding a patent of invention from this period is to find the reference number and year in printed indexes held at The National Archives, the British Library and in several reference libraries. These indexes were published in 1854 by Bennet Woodcroft as a six-volume work called Patents of Invention: from March 2, 1617 (14 James I) to October 1, 1852 (16 Victoriae). Search Google Books using keywords ‘Bennet Woodcroft’ to find copies of some of these indexes online. They are arranged in four sequences:

  • Alphabetical index, of inventors
  • Subject index, of inventions
  • Chronological index
  • Reference index: publication details, and enrolment details

Having found the reference number and the year (for example, Electric batteries, Reference Number 12,697, Year 1849), you can search for the original documents held at The National Archives (or a printed version at the British Library – for advice on this you will need to contact the British Library itself).

Step 2: Move from the published indexes to the printed indexes (in C 274)

Consult the printed annual calendars (arranged by regnal years) held in the Map and Large Document Reading Room at The National Archives in Kew. They are identified by the series reference C 274.

Search for the year you found in the published indexes at Step 1 (you’ll need to convert the year and month to a regnal year) and then, in the respective year, search for the inventor’s name. The calendars usually have some kind of index at the back, or the entries are arranged by initial letter of surname.

Step 3: Convert the printed index reference (in C 274) to a patent roll reference (in C 66)

Patents of invention are enrolled, along with many other types of letters patent, in the patent rolls in C 66.

Most of the entries in the printed indexes in C 274 have been marked up with the modern C 66 reference. If not, you will need to search in C 66 in our online catalogue for the ‘part number’ noted in C 274. This will provide the C 66 reference with which you can order the respective patent roll.

4. Finding specifications up to October 1852

Specifications were enrolled separately in any one of three Chancery offices. The Alphabetical Index of Patents of Invention: from March 2, 1617 (14 James I) to October 1, 1852 (16 Victoriae) in the Map and Large Document Reading Room at The National Archives (see section 3) has been marked up with modern references for many specifications. If you cannot find a reference in that index you need to follow these steps:

  • Step 1: Take the bold reference number from the alphabetical index (see section 3), and look it up in the reference index. This will say (among other information) Enrolment Office, Petty Bag, or Rolls Chapel.
  • Step 2: Convert this to a modern reference using the instructions below, which refer to volumes in the Map and Large Document Reading Room:

Enrolment Office

The index volumes labelled ‘Refers to C 54 vols 164-166’, (C 275) lists entries with the year and part number of the Close Roll on which the specification was enrolled. Search in C 54 to convert this into a modern reference. Specifications for 1849-1853 are all in C 54 and are listed by date in the volume labelled ‘Refers to C 54 vol 161’.

Petty Bag

The alphabetical index has been marked up with all the modern references to C 210. Specifications are also listed by date in the volumes labelled ‘Refers to C 210 vols 1-2’. This contains an index of names in three sequences to match the three sections (‘calendars’) of the lists. Put C 210 in front of the ‘part’ number to get a modern reference.

Rolls Chapel

C 73 or C 54 Look at the volume labelled ‘Refers to C 54 etc., vol 163’ (C 275). For C 73 from 1838 onwards see ‘Refers to C 54 etc., vol 159’. Try both the C 73 section and the C 54 section under the rough date (specifications were filed after patents). C 73 entries have the modern reference written in red. C 54 entries have to be converted, using the C 54 list referred to above.

5. Other patent records

You can find other types of records relating to patents before October 1852 at The National Archives. Search our catalogue with keywords such as ‘patent’ or ‘invention’, restricted to departments BT, HO and SP.

Records include:

  • petitions for patents before 1782, with law officers’ reports, in State Papers Domestic. Search State Papers Online or use the entry books in SP 44
  • petitions for patents from 1782 onwards in HO 42, HO 44 and HO 45, with entry books in HO 43
  • warrants to law officers to draft patents of invention for 1783-1834 in HO 89
  • some reports by law officers, applications by patent agents and disputed cases, 1839-1885, in LO 1

6. Early patents of invention, with no specification

Most early patents give few details about the precise nature of the invention.

Try SO 7 from 1661. These bills, which authorised the issue of letters patent, sometimes include drawings of inventions.

Use the reference index (see section 3), which has an appendix giving abstracts from some early (1617-1745) applications for patents, where no separate specification was enrolled.

7. Records after October 1852

Patents and specifications issued after 1852 are not held at The National Archives. For patents from 1852 onwards, contact the Business and IP Centre at the British Library. The Espacenet database contains information about patents worldwide, from 1836 to the present day. The United Kingdom patent records on the site start in 1890, although coverage is not complete for the period from 1890 to 1930.

The National Archives generally does not hold patents or specifications after 1852. However, we hold many records relating to patents which include:

You can search these records in our catalogue using keywords. Most Patent Office records have the Board of Trade (BT) department code.

You can also browse the Patent Office division in our catalogue.

8. Scottish patents up to October 1852

Scotland had its own separate registration system for patents before 1853. Go to the National Archives Scotland for the records. However, we do hold some records of Scottish inventions in:

  • HO 105, relating to Scottish inventions, 1840-1855
  • HO 106, which can refer to inventions, 1774-1847

9. Irish patents up to October 1852

Ireland had its own separate registration system for patents before 1853, but the records no longer survive. However, you can find some records at The National Archives which refer to Irish patents in:

10. Further reading

British Patents of Invention, 1617-1977: a Guide for Researchers (British Library, 1999) by Stephen Van Dulken