War with France led to the introduction of a wide variety of taxes in Scotland amongst which was this one that lists the ‘Names of owner and number of horses and mules used in husbandry or trade’.
This image at Scotlands Places shows the return made on the 21st of September 1797 for Stornoway from which we can see that Major McIvor of Stornoway had two horses, one of which was liable to the tax, and Mr Colin McKenzie, Minister, had six horses of which three were liable.
Each of these four horses was liable to a Duty of 2 shillings and 3 pence (2s 3d) for Nine Months, with an additional 20% that appears to be referenced to ‘p 37 Geo III’ which I presume to relate to George III’s war chest?
However, what interests me is the manner in which the figures are laid out. For the Duty, we have three columns representing Pounds (L), Shillings (s) and Pence (d) but for the 20% figures an additional column appears after that for pence (although none of the four are labelled)
Now, 2s 3d was 27d (there being 12 pence in a shilling) so 20% of this (one-fifth) was 5 and 2/5 pence.
The table shows this as 5 4, where the 5 is the number of whole pence and the 4 is the number of tenths of a penny.
Thus, in 1797, we see the use of decimal fractions in representing the result of a calculation involving currency.
The Minister, with two horses being liable, had to pay 4s 6d in Duty for the Nine Months, which was 54 pence. 20% of this is 10 and 4/5 pence which is shown as 10 8.
Thus the total to be raised from Stornoway was the princely sum of 6s 9d plus an additional 20% of 1s 4 and 1/5d which is recorded as 1 4 2.
As William Murray, Surveyor, records, this amounts to ‘eight shillings & one penny 2/10ths’.
The smallest coin prior to 1827 was the farthing, which was a fourth (25%) of a penny. I have no idea how the Major and the Minister paid their 4/10ths and 8/10ths of a penny, but I suspect that these were kindly ’rounded-up’ to a halfpenny and a whole penny respectively to help them!