Ye Olde Cambist: Gold Sovereigns, 1817-1890

A Guinea in Mint State weighed 8.387 g. or 0.26966 Ozt. A Guinea less than 8.294 g. or 0.2666 Ozt was no longer legal currency; the loss or 1.438 English Troy Grains rendered the coin 'bullion.'

In 1817, the calculated Mint full weight was 123.2745 grains. Dr. Gregory's lecture refers to an analysis of 1825.

50% of Sovereigns circulating weighed ~123.274
20% of Sovereigns circulating weighed ~122.78
10% of Sovereigns circulating weighed ~122.5245
10% of the Sovereigns circulating weighed ~122.27

1826:
Circulating Sovereigns of 1825 weighed, on average, 123.1926

c. 1830

1833:

Citation: Tables of the Revenue, Population, Commerce, Etc. of the United States &c, Vol. 3 No.16, Coin

1837/8: The average Sovereign circulating in the USA weighed 123.5 grains, in excess of the Mint weight.

Jevons removed 434 average Gold Sovereigns from circulation in Manchester
From Mintage statistics and Jevons' weights and arithmetic sample averages, it's relatively easy to determine with reasonable certainty the reigns/dates of the coins sampled.

In the periods 1817-29 and 1830-39, 49 of the 53 coins were pre-Victorian dates. Assuming all coins by mintage at full weight and then by wear, the discrepancies are perceptible.

In an arithmetic sample, Geo. III sovereigns would have been 10% rather than 2% of the lot; Geo. IV is somewhat overweighed likewise. Factoring mintage, Jevons' coin sample must also be biased to later years in most periods by his own calculations.

Jevons' Sample Total Mintage (Est. Avg.)

Geo. III (1) .................. Geo. III (5) :
1817 (1) ....................... 1817 (3)
..................................... 1818 (2)

Geo. IV (33) ............... Geo. IV (30) :
1821 (4) ..................... 1821 (7)
1822 (3) ..................... 1822 (4)
1824 (4) ..................... 1824 (3)
1825 (6) ..................... 1825 (3)
1826 (6) ..................... 1826 (4)
1827 (3) ..................... 1827 (2)
1829 (4) ..................... 1829 (2)
1830 (3) ..................... 1830 (4)

Wm. IV (15) ............... Wm. IV (14) :
1832 (6) ..................... 1832 (6)
1833 (2) ..................... 1833 (2)
1835 (-) ..................... 1835 (1)
1836 (4) ..................... 1836 (3)
1837 (3) ..................... 1837 (2)

1833 Mint Experiment

The current weight of a Sovereign was 122.5 grains.

1848:

1858:

1860: If the Mint was in operation 253 days per year, between 15,000,000 and 17,000,000 Sovereigns might be weighed and ~250,000 - 500,000 Light Sovereigns would be removed annually, ~ 1.67% - 2.86% or of the coins weighed were light & removed.