Royal Exchange Buildings, central Glasgow, which now houses the Glasgow Museum of Modern Art. This building, situated in a densely built-up area, is delineated on a 1/500 scale map, and has been given assessment number '352', applicable to a particular city ward, in this case Glasgow City Ward X. The image on the right shows this hereditament's position on the wider map. The yellow line on the map marks Ward X's boundary with Ward IX. (National Records of Scotland, IRS118/837).
Identifying which map to inspect in order to obtain an applicable hereditament number can be frustrating, and does require patience and pragmatism. Local knowledge of the area in question is also useful. The first thing to do is establish which 1/10560 (6 inch) standard OS sheet number covers the area in question. There are two ways to do this.
Identifying a Map in the Historical Search Room
The large County/Parish Key sheets can be consulted from which the 6 inch sheet number can be obtained. There is good explanation at the front of this volume on how old OS sheet numbers work, but below is a rough guide to this:
- When surveying areas in greater detail, all OS grid references derive from the overarching 6" sheet (1/10560) for that area. When calculating the position of a 25" grid, the 6" maps are theoretically subdivided into sixteen separate 25" (1/2500) grids, which are numerically ordered as follows:
| 1 |
2 |
3 |
4 |
| 5 |
6 |
7 |
8 |
| 9 |
10 |
11 |
12 |
| 13 |
14 |
15 |
16 |
- If a greater scale map was required for a more densely populated area, a covering 25" grid was theoretically subdivided into four 50" (1/1250) squares, and arranged as follows:
- 25" grids could also be broken down into twenty five grids of 1/500 (127") grids whenever a very urban area, with lots of detail, was mapped:
| 1 |
2 |
3 |
4 |
5 |
| 6 |
7 |
8 |
9 |
10 |
| 11 |
12 |
13 |
14 |
15 |
| 16 |
17 |
18 |
19 |
20 |
| 21 |
22 |
23 |
24 |
25 |
For example, the map showing the Royal Exchange building above is catalogued as OS sheet number VI.11.11 (National Records of Scotland, IRS118/837). This reference translates as 127" grid number 11, which is part of 25" grid number 11 within the wider 6" sheet number IV for Lanarkshire, Glasgow & Environs.
There is more guidance on this technical issue within chapter 5 of Geraldine Beech and Rose Mitchell's Maps for Family and Local History (Kew, 2004). It is important to remember as very often readers are likely to come across IRS maps which contain no boundary details. This means that a bigger scale was deemed necessary by the surveyors, who would label a corresponding, larger scale map with the vital boundary data.
25 inch (1/2500) map of Riddrie, Lanarkshire. This shows how this mapped area has been split into four sepearate 50 inch (1/1250) plan squares by the surveyors, onto which they drew boundaries and numbers for applicable hereditaments (National Records of Scotland, IRS118/77).
Once the correct map is identified, users can consult the manuscript IRS catalogue lists from which a map reference number can be ascertained and input into Virtual Volumes. The maps are arranged alphabetically by county, and then within county by parish, burgh of ward.
Identifying a Map from Home
It is possible to identify which 25" 2nd edition map is applicable to a particular area by using the Scotland's Places website. See below for a search for the village of Aberfeldy:
- Please select the relevant county.
- Select the parish you are interested in by either clicking on the parish location on the map or the ‘refine by parish’ link under the map.
- Select the “2nd and later edition 25-inch” link next to the map.
- Select the plan covering the area of interest. A quick preview of the 'Perth and Clackmannan Sheet 49.06' shows this is the right one for our intents and purposes. Remember that the first part of this sheet number, needs to be translated to Roman numerals (XLIX), to correspond to the original 6" OS grid number.
With this sheet number in mind, a search of the NRS online catalogue will translate this OS grid number into an IRS number. Enter the sheet number and the relevant county name ('XLIX.6' ‘Perthshire’) in the "Search for" field and hit the search button. Three IRS maps (IRS124/145-147) contain information on this particular area. These IRS maps can then be viewed in the Historical Search Room on Virtual Volumes.
This technique is very useful for assessing urban properties, as the map of Scotland on Scotland's Places can be 'zoomed' into, and 25" grid determined quickly and easily, for further investigation in the Search Room.
2. Field Books (IRS51-87)
Once an hereditament number has been identified on a map, its recorded valuation entry can be consulted in a corresponding field book on Virtual Volumes. These are arranged by county, and then within county by parish, burgh or ward. Each field book contains entries for 100 hereditaments applicable to a certain vicinity, so for example IRS87/48 contains information on hereditament numbers for Portpatrick Parish, Wigtownshire, entries 101-200.
These books were pre-printed, and four separate pages were set aside for each hereditament. The details from the returns form, including the details of owners, tenants, and rent, were recorded on the first page. The second and third page were for comments on the particulars of the property such as its building materials, facilities, state of repair, water supply, drainage, land use etc. This was normally quite fully recorded so as to avoid future dispute. These pages were also frequently given over to calculations on the size and value of the hereditament, and occasionally the surveyors found time to create individual sketch-plans of properties, to aid understanding and analysis. These plans were largely excluded from entries post-1912 owning to greater time constraints. The example below for an Aberdeen bakery business gives insight on how well recorded these can be:
Full four-page field book entry for 46 and 48 Park Street, St. Clement's Ward, Aberdeen, owned by a Mrs Jessie Wood (National Records of Scotland, IRS51/14 entry 1332).
The last page of each entry contains the values for the property. They are categorised as follows:
- Gross value = market value of the site, free of encumbrances
- Full Site Value = Gross value of site minus the value of any buildings within it
- Total Value = Gross value minus fixed charges, rights of way and rights of common
- Assessed Site Value = Total Value with the same deduction made to arrive at Full Site Value from Gross Value, but with additional deductions for owner investment on site improvement; it was from this 'datum' value that future increment value duty was assessed.
