Even more than the Time Ball, the One O’Clock Gun has long been a feature of Edinburgh Life. But sound waves, while they travel fast, are not that fast. It takes 11 seconds for the “Report of the Gun” to arrive at Leith. How did the Citizens of Edinburgh allow for this problem and set their timepieces? Researching this question led me into the wonderful world of the Post Office Directory, the World Wide Web of its day….

The Time Gun Map

Piazzi Smyth’s solution was to publish a map of Edinburgh, with red circles of delay printed over the top – see the featured image. This was first done in 1861, the same year that the Gun started operations. A copy of the 1861 map lives at the National Library of Scotland (NLS), and you can see it online here. A prettier version from 1879 is available here. For some time I have been telling people “and this is how the Citizens of Edinburgh set their watches!” But hang on… did ordinary people have this map? Where did they get it?

Publishing the map

As usual in CPS research, my first port of call was the Reports to the Board of Visitors, in the bound volumes of the Edinburgh Astronomical Observations that we have here at the Royal Observatory. In his report of May 27th 1862, published in Volume 12, CPS says

The due correction for the time occupied by the passage of sound has been conveniently given to every householder in the city by Mr Hislop’s “Time Gun Map”, published for the third time within little more than twelve months in this year’s “Edinburgh Post Office Directory”

So lets go find it!

The Amazing Post Office Directories

The NLS have a fantastic online resource. They have digitised Scottish Directories from 1773 to 1911. Not only can you download PDFs, but you can browse and search the directories! They are more than just the Yellow Pages of the day – they had lots of useful information – last posting times, Moon phases, cab rates, classified services.. and maps. I found the relevant PDF for 1861-2, but all I could see was an odd corner of what looked like it might be the map… Time for a visit to the National Library in person..

Humanities research, and going to look at rare books, is a new game to me! I had to put my bag in a locker, and was not allowed to take a pen into the reading room. The books themselves are in 10 subterranean floors. When I had located the record for the item I wanted I submitted a request, and somewhere down in the Bowels of the Earth a staff member set off down the corridors. Two hours later (I went out and had lunch) it arrived and was delivered into my careful hands…

Just inside the cover, the map was there … folded up.

I delicately unfolded it  and finally saw the map in all its glory!

Post Office Directory Fun

As well as seeing the map for myself, I spent a pleasant hour looking at the other wonders contained in the Directory. First, I found Piazzi Smyth’s own entry:

Make sure we don’t confuse Smyth, Chas., professor of practical astronomy, with Smyth, Miss, prof. of dancing… Next, here is a list of Newspapers in Scotland, and Hackney fares:

Here are Sun and Moon rise and set times for June 1861:

Here is an extract from the directory of services, in case you need a Bell Hanger:

And here are some marvelous adverts:

Later years

The map appeared again in the PO Directory for several successive years, but then stopped. The NLS has online a copy of an attractive map from 1879, but this does not seem to appear in the Post Office Directory. Rather, it was perhaps sold directly by W. &A.K. Johnston

Remaining mysteries

What I still don’t know is whether every household automatically or at least normally had the PO Directory, and so the map, or whether normal practice was for Citizens to visit a Post Office to consult. But I had better get on with my day job…

Andy Lawrence, May 2019