This post is dedicated to Gedalya and Aba Neeman (my love’s grandfather and great-grandfather). Their tombstones are engraved with “Loved the work and manufacturing of water pumps in the land of Israel.”
introduction
This revolutionary water pump is the fifth pump in Category V, which is dedicated to “machines for raising water from pools, and from wells which are not deep, and from running streams.”
Fifth water pump, Topkapi manuscript,1206
Al-Jazari gained fame mainly for exotic water clocks full of surprises, like the Castle water clock or the water clock of the peacocks, and for wonderful automata like The Arbiter for a drinking session, among others. Like the four pumps in previous chapters, this pump shows that al-Jazari addressed the real hardships of the people around him. Water pumping is essential to any society for drinking water, watering crops, excess-water and flood pumping, fire extinguishing, and more.
Common pumps in the Islamic world in the 12th century were the Shaduf (Arabic شادوف) and the Saqiya (Arabic ساقية). Both are ancient irrigation tools used to raise water. The Shaduf is fully manual and consists of an upright frame that suspends a long pole with a bucket at one end and a counterweight at the other. The operator pulls the rope until the bucket is full of water. With the help of the balancing weight, he lifts the bucket and pours the water into the irrigation canal. The Saqiya is a mechanical device that uses a donkey or ox to raise a chain of buckets or pots of water.
These two pumps are similar to a human lifting water with a bucket, but they save effort. The water wheel pump does not imitate human action. It can be seen as an extension and development of Ctesibius’s (Κτησίβιος) piston pump, a Greek inventor and mathematician in Ptolemaic Egypt during the golden period of Alexandria. He wrote the first treatises on experiments with compressed air, earning him the title “father of pneumatics”. He invented the first piston pump, which was apparently very popular in the Roman Empire. At least twenty-five such pumps were found in excavations of Roman sites. You can read more here. None of Ctesibius’s writing survived; we know him only through later writers who quoted his work. I don’t know about Ctesibius’s pumps in the Muslim world, and al-Jazari’s book doesn’t mention Ctesibius. We shall never know what, if any, information about Ctesibius was available to al-Jazari.
How does al-Jazari’s water wheel pump work?
The technical explanation, as always, will be colored in blue, so anyone who is not interested in intake or discharge valves can skip those bits. This is a short YouTube clip from “Technology Science in Islam” explaining the operation of the pump:
The pump’s energy source is the water wheel, driven by water flow. The water wheel is connected through gears to a wheel with an eccentric pin (positioned not in the Center) within a rail inside the crank connected to a fixed point. As the wheel turns, the rod moves left, pulling one piston and pushing the other. This mechanism is called a slider-crank mechanism, and it converts straight-line motion to rotary motion, as in a reciprocating piston engine, or rotary motion to straight-line motion, as in a reciprocating piston pump. This mechanism is essential to modern machinery.
Slider crank mechanism
Two pistons are attached to suction pipes going down to the river. The suction pipes continue upward and come together to a single supply. The suction pipe has two one-way valves: the intake valve and the discharge valve. This is a modified drawing of the piston and the valves. In al-Jazari’s original drawing, there is no water, and both valves are closed, which is possible only during construction and impossible during pumping. In addition, in the facsimile edition, the drawing is cut:
Piston and valves, modified drawing
When the piston moves backward (as in the drawing), the intake valve opens, and the discharge valve is closed. This disconnects the pump from the supply line and draws water from the river. When the piston moves forward (pushed), the intake valve closes, and the discharge valve opens, pushing water upward in the supply pipe. This mechanism is called double action because when one piston is pushed, the second is pulled, keeping the water supply continuous.
Al-Jazari’s pump has three major innovations compared to Ctesibius’s pump. Each one would justify a separate patent today. Online lists of what al-Jazari invented include, for example, here or here. The concept of patent rights is foreign to Al-Jazari and to the 12th century in general. In a future post, I hope to write about the history of patents and the concept of intellectual property in The Book of Knowledge of Ingenious Mechanical Devices.
- Ctesibius’s piston pump was manual and required human operation. Al-Jazari used a water wheel to power the pump. Al-Jazari also writes that the water wheel is like the one used to rotate millstones, which were well known at his time. This was a major advantage for pumps used for drinking water or irrigation.
- The waterwheel converts circular motion (the waterwheel) into linear motion (the motion of the cylinders). The history of the crank (in various forms) dates back to the 2nd century BC in China. Al-Jazari knew of the “Banu Musa” book, which includes a crankshaft. But the crank-slider mechanism is more efficient and remains in use to this day, without significant changes.
- Ctesibius’s pump only works when immersed in water. If the water level drops, it stops pumping. Al-Jazari’s pump has suction pipes that let it function properly above the river’s water level. A decrease in water level (up to a point) should not affect it at all.
Was this pump built, or is it just an idea?
Occasionally, someone wonders whether al-Jazari actually built his machines or whether they were just fantasy blueprints or suggestions that never materialized. Unfortunately, we don’t have any proof. The Palace in Diyarbakir was only partially excavated, and no archaeological evidence of al-Jazari’s machines has been found. I don’t know of any external evidence, for example, a Muslim traveler visiting the Palace in the 13th century who could report on an exotic machine like the elephant clock. However, I’m convinced that the pump, like the Palace door and Castle clock, described in previous posts, was indeed built. I have two arguments:
- The number and level of detail make you feel that this pump was built. For example, a rope wrapped around the copper piston to improve sealing. The very use of the rope hints at an improvement cycle. It is hard to assume that this was a part of a design that never came to life. Moreover, al-Jazari is very specific and requested a rope made from cannabis used at his time by sailors. This rope was probably selected for its resistance to water. Could al-Jazari have thought through all these details even though the pump was not built? Possible but not very likely.
- In 1976, the London Science Museum built an accurate model of the water wheel pump. The only difference was that the pump was powered by electricity, not the Thames. A picture of the model is below. The model produced a steady stream of water with zero problems. Al-Jazari may have been a wonderful designer, and the museum team may have been the first to realize his design, which worked well on the first try. It is more likely that moving from the drawing board to a real machine requires iterations and improvements, as experience has often shown. The Museum staff’s success relies thus on the practical experience of al-Jazari’s pump.
Pump reconstruction. London Science Museum
Aba Neeman Pumps Ltd.
In 1980, I studied Chemistry at Tel Aviv University and looked for a summer job to make ends meet. I don’t remember exactly how it was arranged, but I went to work in the factory “Aba Neeman Pumps Ltd.”, which was owned and managed by the grandfather of my love, Gedalia Neeman. On my first day, I helped cast impellers in the sand. It was quite similar to what al-Jazari did 800 years before me. I don’t want you to have the wrong impression about my technical skills at the time. I got a 5-minute explanation about the task, and by the end of the workday I broke unneeded bronze parts with a hammer. The offices were tiny, and no one needed my chemistry or computer know-how. Most of the summer I was an apprentice to the lathe operator. It was wonderful. I enjoyed it so much that I took an evening course in Lathe operation. Aba Neeman built the factory in 1900. He was a real autodidact; His formal studies amounted to a “Yeshiva”, a Jewish educational institution that focuses on the study of traditional religious texts. He learned everything he knew about machines through work and experimentation. He worked in Leon Stein’s metalwork workshop, which did all the metalwork the young Jewish community in Israel needed: repairing wagons, maintaining pumps, and repairing the steam boiler at the winery in Zichron. Without electricity or engines, the lathe was operated by leg power, like old Singer sewing machines. Such a manual lathe was the beginning of the factory. Aba Neeman specialized in water pumps and, amazingly, the only difference between the pump Aba Neeman made and al-Jazari’s pump, explained above, is that Aba Neeman’s pump was powered by a diesel engine, while al-Jazari’s was powered by a water wheel.
The Author and farmer Moshe Smilanski wrote that “the pump of Aba Neeman was working for 44 years with no problems” (from “Inventor and Efforts” by Saul Avitsur [Hebrew]). This was not eight hundred years ago, but only in the last century, yet both “the farmer-writer” and a pump that lasts 44 years feel so distant that they create a sense of yearning, like Al-Jazari.