Definition of "quartern"

In half a minute Mrs. Cratchit entered—flushed, but smiling proudly—with the pudding, like a speckled cannon-ball, so hard and firm, blazing in half of half-a-quartern of ignited brandy, and bedight with Christmas holly stuck into the top.

c. 1884, Charles Dickens, Their Christmas Dinner, New York: Geo. R. Lockwood & Son, page 12

...I find that you, in recording the longevity of incumbents (1st S. xi. 407.) notice that the quartern loaf was on the 5th March, 1801, at the enormous price of twenty-two pence halfpenny, happily at this moment only two-fifths of that amount...

1861 March 2, Σ. Σ., Notes and Queries (2), volume 11, number 270, London: Bell & Daldy, Minor Notes, page 168

Let those who used to gibe at diplomacy and cry out against armaments consider how our manufacturing population is to be employed when half our exports are gone how our crowded cities are to be fed when ten millions of our workmen are out of work and the quartern loaf is at a shilling how are our industries to be started when the banks are bankrupt and the Exchequer has to find interest on a war indemnity of two thousand million sterling.

1914, Frederic Harrison, Written for the Victoria League, The Meaning of the War; For Labour—Freedom—Country (Pamphlets on the European Crisis), London: Macmillan and Company and Richard Clay and Sons, Ltd., page 4