Paraffin
2 of the 6 encyclopedias on this shelf carry an entry for Paraffin. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a tasteless, odorless, fatty substance proof against the action of acids and alkalies. It is a residuum obtained by heating wood, peat, soft coal, or wax, in a retort. Large quantities are left behind in the refining of crude petroleum. Paraffin is used for a variety of purposes. Laundrymen use it to give a polish to fine linen. Cartridges are coated with it to prevent their sticking in the gun barrel. Paper and cloth are treated with paraffin to render them waterproof. It makes excellent candles, equal to the best wax. Housewives pour a film of melted paraffin over their preserves and canned fruit to protect them from germs in the air. Scientists desiring a thin shaving of a substance to place under the microscope imbed the tissue in paraffin to hold it firm for the knife. Paraffin is used in the manufacture of chewing gum. Brewers coat the inside of beer barrels with paraffin. It is used in the insulating covering of electric wires. Great Britain supplies the greater part of the paraffin of commerce. Much paraffin is obtained from the soft coal near Bonn, Germany. The paraffin made in the United States comes chiefly from Bradford, Pennsylvania.
Collier's New Encyclopedia (1921)
or PARAFFINE, a solid, fatty substance, produced along with other substances in the dry or destructive distillations of various organic matters, such as coal, bituminous shale, lignite, peat, etc., at a low red heat. It is found along with liquid oils in petroleum, and in the native state in coal and bituminous strata, known as fossil, wax, ozokerite, etc. Paraffin is a mixture of several hydrocarbons, probably homologues of marsh gas of high atomic weight. Many of the paraffins are found ready formed in petroleum and other mineral oils. In mining, a name adopted for a group of native hydrocarbons, having the general composition: Carbon, 85.71; hydrogen, 14.29 = 100. It embraces the species urpethite, hatchettite, ozocerite, zietrisikite, and elaterite.
What Has Changed in the Last Century
The chemistry in these entries has held up: paraffins are indeed "homologues of marsh gas" — what we now call the alkane series, methane and its relatives — though a modern chemist would say molecular weight rather than "high atomic weight." What has moved is the supply. Aiton's claim in 1910 that "Great Britain supplies the greater part of the paraffin of commerce" rested on the Scottish oil-shale industry founded on James Young's process; the last of those works closed in 1962, and virtually all paraffin wax now comes as a by-product of dewaxing petroleum lubricating oils rather than from retorting coal, peat or shale. Most of the listed uses survive — candles, waterproofing, electrical insulation, and above all the paraffin block still used to embed tissue for microscopy — but the housewife's "film of melted paraffin" over preserves is now advised against by food-safety authorities, since the seal cracks and traps mould rather than excluding it.
Written for this edition, 2026.