Mustard
2 of the 7 encyclopedias on this shelf carry an entry for Mustard. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
various species of the cruciferous genus or sub-genus Sinapis. Also a condiment obtained by grinding and sifting the seeds of black and white mustard. The flour produced forms the genuine mustard of commerce. The seeds yield by pressure from 18 to 36 per cent. of a fixed oil, and, after macerating with water and distilling, a small quantity of a highly pungent and volatile oil. MUSTARD GAS. Dichlorethylsulphide, A water-white liquid boiling at 219° C., first prepared by the German chemist, Victor Meyer, in 1886, and first used in warfare by the Germans at Ypres, July 20, 1917. In the following February, the English chemist, Pope, reported the discovery of a process of manufacture by absorbing ethylene gas in sulphur monochloride. His process, with some modifications developed by the U. S. Chemical Warfare Service, was adopted by the Allies throughout the balance of the war. The liquid has a corrosive effect on the skin, raising painful blisters, slow in healing, and has a tendency to eat further and further in, sometimes even corroding the bone beneath the flesh. strong, also blisters, The vapor, when particularly when the skin is moist or greasy. The eyes, being moist, readily absorb the gas, are rendered very sore and roll up under the lids, staying up for some days, after which the sight is usually recovered. The vapor also attacks the lungs, sometimes resulting in complete destruction of the tissue. When it was first introduced, 4 per cent. of all mustard gas casualties were fatal, but toward the end of the war fatalities dropped to less than 1½ per cent. The gas is very persistent and a shelled district takes from two to seven days to clear. Rain washes it into the soil, but warm sun will bring it out again. At low temperatures, it becomes a yellowish grease, and to prevent freezing in the MUSTELIDÆ a solvent is added, chlorbenzene or carbon betrachloride being commonly employed for this purpose.
Aiton's Encyclopedia (1910)
an herb belonging to the same family as the horseradish, turnip, rutabaga, radish, shepherd's purse , and pepper-grass. The white mustard and the black, the most commonly known species, are both from Europe. Table mustard is obtained by grinding the seeds of the black mustard. Flour of mustard is obtained by hulling the seed and rejecting the bran,--though with loss of strength. The production of table mustard has assumed large proportions. Natural scenery, both in Great Britain and in America, is defaced by huge lettered signs proclaiming the virtues of some particular brand of table mustard. Mustard is a pest in the great wheat fields of the southwest, where, once established, it perpetuates itself, until weeded out or destroyed by summer fallow. A solution of copperas, sprinkled on the top of the mustard when it is about eight inches high, and before it blooms, destroys the plant. Seventy-five cents for material and labor covers the cost of spraying an acre. Grains and grasses seem to receive no injury from the spray; but turnips and radishes, both of which are members of the mustard family, are injured quite as readily as the mustard itself.