In a post a long time ago I talked about one of the many difficulties in interpreting historical recipes (and there are many) is that a pound or a gallon or a number of other measurements have not always been the same everywhere or in every era.
It is also true that a hundred did not always equal 10 x 10. This did not matter to the ordinary household cook, but it was very important to anyone buying or selling commodities.
In 1440, in the great fishing town of Yarmouth, a regulation was established (or confirmed) that:
Hearings [herrings] are sold freshe by the meise, which is five hundred, eche hundred contayning
That is, a “hundred” of herrings was actually one hundred and twenty herrings. This was technically a “long hundred,” but the “long” was often understood. There was a lot to “understand” however because the actual number represented by a long hundred depended on the item and the era.
Fish were commonly traded in long hundreds and this usually indicated six score, or 120, as in the fifteenth century reference above. It could mean more however. A reference in the Household Ordinances of Edward II (1284-1327) noted that “Of somme manner of fish the hundred containeth six score, and of some other sort, nine score.” A seventeenth century reference says “Ling, Cod, or Haberdine, have 124 to the Hundred.” It could even mean as much as nine score, or one hundred and eighty. Other items commonly counted in long hundreds were eggs (120,) sheep in some areas (106,) dried salt fish (160,) and onions and garlic (225, made up of 15 “ropes” of 15 heads each.)
Complicated, isn’t it? Anyway, just in case you have a lot of herrings and eggs, how about a nice herring omelet?
Beat up any quantity of eggs you think necessary, with fine salt and pepper, parsley and green onions shred very fine; put some butter into a fryingpan, let it melt, and then put in the eggs; fry the omelet till it is of a good colour underneath, and. turn it into a dish for table. To make any particular omelet, as with bacon, veal kidneys, heads of asparagus, truffles, morels, or mushrooms, the ragout must be first made, seasoned as you wish, and, when cold, minced, that it may mix well with the eggs; beat the whole well together, and then make these omelets in a fryingpan, the same as others. Regulate the seasoning of the omelet according to that of the ragout, taking care that it be not too highly seasoned.
Omelette aux Harengs Sorés (Red Herring Omelet)
Open the herrings at the back and broil them, then mince and put them into the omelet: do not add any salt to the eggs and finish the omelet as others.
French domestic cookery, by an English physician 1825.