Franz Ritter von Soxhlet is credited with inventing an extraction apparatus in 1879 that now bears his name. Soxhlet was a German agricultural chemist of Belgian “extraction” from Brünn (now Brno in the Czech Republic) working in the area of milk characterization at the Vienna Agricultural Institute.
Soxhlet spent most of his career in the analysis of milk and its constituents. In an attempt to isolate the fatty constituents from milk, he (and students) had been attempting to use an extraction apparatus developed by another Brno chemist, Professor Zulkowski. Soxhlet developed a technique whereby milk was absorbed into a quantity of calcium sulfate powder and then submitted to extraction by ether. The Zulkowski apparatus proved problematic, however. Solids were able to find their way over the extraction tube and into the solvent reservoir. Modifications of the design also suffered from inefficiencies that apparently required extended operation.
A student of Soxhlet, a Hungarian fellow by the name of Mr. Szombathy, contrived a solution to the problem. Szombathy is credited with coming up with the clever siphon feature that so distinguishes what we now call the Soxhlet extractor.
It has been lamented that the efficiencies gained by the siphon discharge design have been partially lost due to the entertainment effect. Generations of chemists have dropped what they are doing to stand and watch the collection thimble fill and subsequently discharge dramatically through the siphon. You have to take your fun where you can find it.
Well done, Szombathy!
Lamentations on Chemistry 
Imagine a six-foot tall assembled Soxhlet sitting atop a 5-liter flask containing some 3 liters of pyridine, nestled in a very large heating mantle. Big thimble (and topped with a tucked Kimwipe to prevent solids splashing; saturate the solids before starting.). Now imagine running for some large-bore accordian hose to explicitly vent its exhalations into a hood. Lots of glass wool and aluminum foil insulation.
Kerogen (the organics) cannot be removed from oil shale (that isn’t shale and doesn’t contain oil) without severe degradation. The rock, however, can be removed from the kerogen. Toluene, pyridine, then methanol to first wash bitumen from about 10 kg of -40/+60 pulverized oil shale. I said I needed 10 grams to start. The engineer pointed to a rubble pile and said “mass balance”. My tech did the rotovaping.
The final fluffy product spontaneously smoldered in air. After opening a vial and pouring its contents, the project manager said, “do you have more?” Oil shale is America’s hydrocarbon hope for the future – just add government subsidies.
Was this extractor custom build or assembled from available pieces parts?
It was scrounged from a defunct chemical company at auction for about $0.10 on the dollar by Pete Digiacomo. In the 1980s it was a commercial product. It languished on our bone pile until the day (about three weeks, one for each solvent plus drying in-between in a vacuum oven) Toss the vacuum oven fittings. Ball valve for vacuum, rotary valve for backfill (never use a needle valve for sealing anything). Gas conductance varies as the fourth power of inner diameter. My large liquid nitrogen traps were blown one piece and connected “backwards”. They didn’t clog, they collected.
We had an I2R power cutoff on the water outlet hose. Failure was not an option. IIRC, somebody in suit came by and asked wy it wasn’t on the inlet hose. “It works better with warm water”; then they went away.