Isaac D'Israeli (1766-1848) - English man of letters, father of Benjamin Disraeli. His father, Benjamin D'Israeli, an Italian Jew, migrated from Venice to London in 1748 and amassed a substantial estate. Isaac passed his life in quiet and almost uninterrupted study, publishing a number of novels and books of informed essays on literature, history, and the curiosities of life. In 1813, in a quarrel with officals of the synagogue in Bevis Marks, he converted to Christianity. He had his surviving children baptized about 1817. As a Jew, Benjamin Disraeli would have been barred by English law from a political career.

Charles Darwin(1809-1882) - English naturalist, author of The Origin of Species(1859). A close friend of Sir Charles Lyell, he took Lyell's Principles of Geology with him on the voyage of the Beagle, and saw much of Lyell in the years after his return to England. He was also influenced by Malthus's theories on human population dynamics, among the gloomiest theories of a dismal science.
An introduction to evolutionary biology
More about Darwin
Darwin's major works, online and searchable

Difference Engine - A machine to compute numbers mechanically, conceived of and constructed by Charles Babbage. The first Difference Engine, completed in 1822, was basically an adding machine for the computation of polynomials, and worked to an accuracy of six decimal places. Babbage then proposed a larger Difference Engine, accurate to twenty decimal places. He received a grant of about £17,000 for this from the British government, but was unable to have levers and cogwheels made to the tolerances he required, and the machine was never completed.
Two Difference Engines
Calculating Engines and the Factory System by Simon Schaffer

Dinosaur awareness - Before 1877, only scattered dinosaur bones had been found in Europe and the United States. In that year, however, large finds were made in Colorada and a mammoth bone bed was discovered in Como Bluff, Wyoming. Trainloads of dinosaur bones were shipped east and reassembled in museums, popularizing dinosaurs with the public.
Awareness of dinosaurs, 18th and 19th centuries

Benjamin Disraeli (1804-1881) - Earl of Beaconsfield, British statesman and novelist, Prime Minister in 1868 and from 1874 to 1880. Not at first well-received by Parliament, perhaps due to his dizzy theatricality of style, he ended his maiden speech prophetically: "...though I sit down now, the day will come when you will hear me." By 1834, he was well established in politics and high society, and depicted them both in his novels of that period, sometimes including portraits of prominent men and women. Even in his own time, his novels were popular rather than critical successes -- Sir Anthony Trollope found them "spurious," and Wordsworth thought them "trashy." As his political duties became more pressing, he withdrew from novel writing, and didn't publish any at all for more than twenty years. Regarding contemporary scientific theories, he rhetorically asked an Oxford audience in 1864: "Is man an ape or an angel? I, my lord, am on the side of the angels. I repudiate with indignation and abhorrence those new fangled theories."

The Doctor-Bronner Effect - The epiphany that comes with the realization that everything in the universe is connected to everything else.

Dolly - British slang for penis, current from the 19th century. Also tramp slang for a candle.

Dollymop - In Cockney dialect, an "amateur" prostitute, from about 1855.

Draft riots, U.S - Conscription for compulsory military service began in the United States with the Conscription Act of 1863, which also allowed wealthy conscripts to hire substitutes to take their place in the army. This resulted in civil disturbances in some places, the worst being in New York City, where hundreds of lives were lost, thousands of people injured, and one and a half million dollars in property destroyed. Starting on July 13, 1863, the riot was quelled four days later by Federal troops.

The Difference Dictionary was first published
in slightly different form in Science Fiction Eye, Issue #8.
Text copyright 1990, 1996, 2000, 2003,
by Eileen K. Gunn.