Dishwasher

Cochran claims dishes held in fitted wire racks while jets of hot soapy water are thrown at them. Note the key idea: the water moves, the dishes don't.

Bend stiff wire into slotted cradles sized to hold a plate on edge and a cup upside-down. Each dish gets its own compartment so nothing knocks together.

Set the loaded rack inside a basin that will catch the water. This is the wash chamber.

Dirty a dinner plate with a little butter and crumbs, and rack it. This is the mess the machine must clear without scrubbing.

Fill a large syringe with hot water and a drop of dish soap. Squeezing it fires a focused jet — your hand-powered pump.

Aim the jet across the plate's face. The moving hot suds lift the grease and wash it away — no cloth, no rubbing. Watch the food go.

Play the jet over the whole plate. In the real machine a spinning arm or rack does this so every surface is struck in turn. The plate stays put.

Wash a second greasy plate by hand in the same water. Your hand rubs the china and the water turns greasy fast — the jet kept clean water hitting the plate.

Jet one plate with lukewarm and one with hot (safely warm) soapy water. The hot jet cuts grease far faster — heat melts fat, which is why the machine boils its water.

Refill with plain hot water and jet the plate again to rinse off the suds. Two cycles — wash, then rinse — exactly as the machine does.

Leave the dishes in their wire cradles to drain and air-dry. The rack doubles as a drying stand — you never touched the clean china.

Inspect the jetted plate: clean and unchipped. Because nothing rubbed or knocked it, delicate porcelain survives — Cochran's whole reason for building it.

The patent. US 355,139, "Dish-Washing Machine", granted 28 December 1886 to Josephine G. Cochran of Shelbyville, Illinois. (Her surname is often spelled "Cochrane" today.) A well-off widow, she was furious that hand-washing chipped her inherited china, and reputedly declared, "If nobody else is going to invent a dishwasher, I'll do it myself." She measured her dishes, designed a wire rack for each, and had the machine built in a shed behind her house.

The principle is jet-washing, not scrubbing. Earlier "dishwashers" had scrubbing brushes or a hand that raked the dishes — they broke crockery and cleaned poorly. Cochran's insight was to hold each dish motionless in its own compartment and let pressurised hot soapy water do the work (steps 5-7): moving water shears grease off a surface without any abrasion, and hot water melts the fat so it lifts away (step 9). A boiler heated the water, a motor-or-hand pump drove the jets, and the wash-then-rinse cycle (step 10) left the dishes clean and, crucially, unchipped (step 12).

Why it mattered — and why it waited. Cochran's machine won an award at the 1893 Chicago World's Fair and sold to hotels and restaurants, which had mountains of dishes and staff who broke them. But home kitchens of the 1890s often lacked the plentiful hot water and, later, the electricity the machine wanted, and many households still had cheap labour to wash up — so the domestic dishwasher did not become common until the mid-twentieth century, when piped hot water, electric motors and a smaller servant class finally arrived together. Her company survived and became part of KitchenAid; every dishwasher today still does exactly what your syringe did — holds the dishes and throws hot water at them.