When recently issued U.S. patents are examined, one finds two dates that tell when the application was filed and when the patent was granted or issued. The situation is somewhat different when early British patents are examined. The following briefly explains the meaning of the dates in that case.

Three dates appear on early British patents. As an example, the patent granted to Edward Augustin King (or J.W. Starr) for two lamp designs will be considered. This patent has "A.D. 1845.......No. 10,919." at the top of the pages. Within the document the three dates, in the order in which they appear, are: 4 Nov (1845), 2 May 1846, 4 May 1846. It can be seen then that the patent number is identified with the first date.

The first date is the date of application, the second is when full patent specifications were submitted and the third date was called the date of enrollment; it was the date on which the patent was granted. It follows, therefore, that King's patent was applied for in 1845 but issued in 1846.

Apparently "Patents between 1617 and 1852 were not officially published until a gentleman named Bennett Woodcroft, who was the Superintendent of Specifications and Indexes in 1852, implemented many changes including an extensive programme of publishing. All patents between 1617 and September 1852 were numbered and printed along with those from October 1852 onwards.

"Patents pre 1852 were applied for in theory only with the actual specification being presented within six months of this date and then 'enrolled' a few days later at one of the three Chancery Offices of the applicants choice."

As it regarded the King (or Starr) patent—

"Prior to the Patent Law Reform Act of 1852 the grant of a single patent did not apply to the whole of the United Kingdom. Separate grants were required for each of England, Ireland and Scotland.

"In Scotland application for a patent was made to the Home Secretary. A warrant was issued and 'Sealed', the specification itself was to be lodged with the Chancery Office within four months. Once all this was done the granted patent lasted for (normally) fourteen years. Today (2001) the specifications are held in the care of the Scottish Record Office at Edinburgh.

"Something the British Library does hold...is a volume titled 'Scotland, Alphabetical Index of Patentees 1767 to 1855.' There is an entry under the year 1846 - no exact date is given - for Edward Augustin KING, the title of the invention is listed as 'Light by Electricity.'"

As an aside, the second patent granted to Edward Augustin King (for Magneto-Electric Machines) carries the following three dates: application, 30 Apr (1846); date of full specifications, 30 Oct 1846; enrollment, 30 Oct 1846.

The writer is indebted to Maria Lampert of the British Library for much of this valuable information.