The deleterious effect of copper sulphate on green peas
U 16.801: Sulphate of copper poison SO4 or something in some dried peas he remembered reading of in a cheap eatinghouse somewhere but he couldn’t remember when it was or where.
The use of copper sulphate (CuSO
The experiment was deemed a success.
But in 1900 the Weekly Irish Times for 16 June reported some bad news on the use of copper sulphate as a weedkiller:
In general the impression was growing that copper sulphate was something of a mixed blessing.
Copper sulphate had another use, too. From at least the mid nineteenth century greengrocers were finding themselves in court throughout Britain and Ireland for selling vegetables, and especially bottled peas, which had been treated with copper sulphate to ensure an attractively vivid green appearance. The London Times and regional papers reported cases throughout the latter part of the century. The Irish papers picked up these reports, such as one published in the Weekly Irish Times on 25 June 1881:
The Food and Drugs legislation did not specifically prohibit this practice, but magistrates used their discretion. A common defence was that the peas had been bottled in France, and bought in good faith; the cases do not seem to be concerned with ‘dried peas’, as Joyce perhaps inaccurately remembers.
It seems that Joyce encountered some reference to the practice, and refers passingly to it in Ulysses. One report appeared in the Weekly Irish Times on 8 April 1905, discussing a case from Londonderry:
It was stated that ‘sulphate of copper preserved the appearance of the peas, but it was dangerous to health’. The defendants were fined £3 and costs.