This is the second basin of al-Jazari for blood-letting, “from which the quantity of blood which it holds can be ascertained.” Its mechanism is almost identical to “The Basin of Monk,” explained here with some additional background on the history of bloodletting. The main difference is in the design; two scribes are sitting on a raised platform, one writer rotates, and his pen indicates the amount of blood collected in the same manner as the monk. The other scribe has a writing pad that rises so that his pen, which does not move, indicates the amount of blood. We have plenty of information, medical and images which documented bloodletting. There is no precursor bloodletting tool before al-Jazari and all bloodletting tools after his time are simply bowls with marking. And the question is why?
How Does it work?
The mechanism is almost identical to the basin of Monk. The differences are so tiny, if the readers are interested in them, he or she probably do not need my mediation. Still, for the comfort of my readers, I provide my adaptation of the modern drawing by Donnell Hill, the book translator and annotator. If there are any errors, the responsibility is all mine. The technical explanation, as always, will be colored in blue, so anyone who is not interested in pulleys or balancing weight can skip those bits.
Both scribes are sitting on an elevated platform on four columns. The scribe to the left sits on the main pulley and is holding a pen which is an indication of the amount of blood collected so far. Two ropes are connected to the main pulley through the hollow columns and two small pulleys. At one end there is a float, and the other end has a balancing weight. The ropes are tight before the beginning of the bloodletting, and the pen is indicating zero. The blood goes to the basin and the drain and is collected in the container where the float is located. As a result, the float goes up and release rope through the pulley, the weight continues to pull down, and the main pulley with the scribe on it would rotate. The float is also connected to a rod with a writing pad at the end. As the amount of blood accumulates, the writing pad will rise as well. The fixed pen in the hand of the second scribe would also indicate the amount of the blood.
Bloodletting tools throughout history
I don’t know if there are any other medical procedure as bloodletting that got so many medical or artistic expression. This is just a small sample:
Pictures from right to left:
- A drawing of bloodletting on a Greek vase from the fifth century BC
- A Bowl with a scene of bloodletting from Iran, the first half of the 13th century, Islamic Art Museum, Berlin.
- Caricature of bloodletting by James Gillray, 1804.
Pictures from right to left:
- A Physician is letting blood, 13 century, Aldobrandino of Siena. British Library, London.
- A surgeon binding up a woman’s arm after bloodletting. Oil painting by Jacob Toorenvliet, 1666.
- Photo of bloodletting from 1860, one of three known photographs of the procedure.
In all these photos and many others, the blood is collected in a bowl. In 1979 the Smithsonian Museum published an impressive catalog of bloodletting tools. The catalog is available online and is full of great information including an article summarizing the topic and plenty of images of bloodletting instruments; there is nothing more than a bowl with graduated marking:
How do we explain al-Jazari choice?
Quite a bit of al-Jazari work relies on his predecessors. Al-Jazari himself was the first one to reference previous scholars as I showed in the Castle Clock or in The Fountain of the Two Tipping Buckets (in Hebrew). Sometimes the technological leap forward is very large, for example, water wheel pump and sometimes less significant as in all the fountains. But not only that there is no precedent to al-Jazari’s designed for measuring blood there is no ” sequel”; no one used al-Jazari ideas. It is worth mentioning his book was quite popular; there are not many manuscripts from the 12th century with 15 remaining copies and bloodletting continued for about 700 more years.
Surprising? Maybe not. Al-Jazari solution is complicated and requires a lot of work. There is no comparison between the serial production of a ceramic bowl even in the 12th century, and fine mechanics. The materials are more expansive, the basin is made out of brass, and the scribes are made of copper. All this raised the final cost. Also, al-Jazari’s solution is much more difficult to clean and maintain, and offers only one clear advantage: it is more fun and allows the patient to track the amount of blood easily.
I have no evidence in the text, but I am convinced that al-Jazari understood the cost of material, the amount of work and the complexity of maintenance as well as I do. So why did he chose as he did? I have two proposals, and you are welcome to offer your own.
- I discussed this question with my young son. He said that if I were asking him in sixth grade to invent a tool that measures the amount of blood during bloodletting, he would look for a solution like this (he added a lot of limitations due to what he knew at that time) because it’s much more “cool.” Al-Jazari was an engineer serving in the Palace in Diyarbakir. The cost was no consideration for his employers, and there was no shortage of servants and slaves. However, his love for automatons constantly sought surprising solutions to the problems around him. This combination of an engineer “crazy” for automatons without constraints won’t be back.
- My love M. turned my attention to the Linguist Roman Jakobson and his much-cited article “Linguistics and Poetics” which maps the language to its essential function. For example, The referential function corresponds to the factor of Context, and its role is to transmit information. Some say that this is the main function. I want to focus on the poetic function; it focuses on the message himself, rather than the addresser (sender) or addressee. I took the liberty to take a post of her (in Hebrew) “One Great Illustration and Ora Eitan” and modify it slightly:
“According to the linguist Roman Jakobson” The primary intent of the message as such [in our case, the message is the automaton itself, the way it fulfills its purpose. AG] is the poetic function of language. In Jakobson words: The set (Einstellung) toward the message as such, focus on the message for its own sake, is the POETIC function of language.”
In these terms, al-Jazari is a poet or at least a poet of automata. In this respect, the discussion on price or maintenance misses the point completely because it treats poetry with traditional engineering tools.