Despite the early emergence of balances and practices of weighing, it was only at the turn of the seventeenth century that they were applied to the human body. During this time, the physician Sanctorius Sanctorius (1561–1636) devised a special weighing chair to undertake a series of weighing experiments to measure and to quantify physiological processes. As trivial as quantitative assessment with regard to health issues might seem to us today, it was a highly innovative step at the time. By experimenting with the weighing chair, Sanctorius introduced the idea of quantitative research into physiology.
Portrait of Sanctorius Sanctorius. Source: By kind permission of Comune di Padova - Assessorato alla Cultura.
Skull of Sanctorius Sanctorius. Source: By kind permission of Università degli Studi di Padova.
Historical accounts of Sanctorius and his work tend to present him as the inventor of a new medical science that profoundly changed modernity. Measurement and quantification became important parameters of medical research and numerical values and mechanical aspects were increasingly applied in this field. Given the important role that Sanctorius holds in these accounts, it is striking that the reception of Sanctorius’s ideas in the seventeenth and eighteenth centuries and the historical accounts of his work lack a profound discussion of the design of his weighing chair and of the measuring method he applied to the weighing experiments. This project addresses this gap. In collaboration with the workshops of the Technical University of Berlin (Institute of Vocational Education and Work Studies), we reconstructed the weighing chair of Sanctorius. In a second step, we experimented with our reconstruction and constantly adapted and improved it according to the experiences that we gained in the process. We did so in the context of a seminar that was held as part of the curriculum of the History of Science Department at the Technical University of Berlin. This allowed us to develop a new perspective on Sanctorius’s undertakings and made us reconsider the function and purpose of the Sanctorian chair.
Watch the Construction of the Sanctorian Chair
Reconstruction of the Sanctorian Chair: A Photo Diary
Click on the picture to open the slideshow
Discussing the design of the Sanctorian Chair with students as part of a seminar held at the TU Berlin in 2017, © Paul Weisflog.
Further discussions, © Paul Weisflog.
Design plan and position list, © Paul Weisflog.
Final design plan and position list, © Paul Weisflog.
Simulation test to establish a first understanding of the design and to experience the forces at work, © Paul Weisflog.
Placing the weight on the end of the beam, © Paul Weisflog.
Sitting on the simulated chair, © Paul Weisflog.
Bringing the simulated balance into a stable position, © Paul Weisflog.
Finding the equilibrium position, © Paul Weisflog.
Choosing the material, © Paul Weisflog.
Cutting the wood with a circular hand saw, © Paul Weisflog.
Discussions in the Workshop, © Paul Weisflog.
Introduction to the panel saw, © Paul Weisflog.
Using the panel saw to cut the wood strips, © Paul Weisflog.
Working with the planing machine, © Paul Weisflog.
Cutting the seat of the chair, © Paul Weisflog.
Working on the suspension of the chair, © Paul Weisflog.
Grinding the steel rings used for the first version of the suspension of the chair, © Paul Weisflog.
Determining the position of the wood plugs, © Paul Weisflog.
Plugging, © Paul Weisflog.
Gluing the chair together, © Paul Weisflog.
Drying of the glue, © Paul Weisflog.
The frame to hold the reconstruction, © Paul Weisflog.
The first result, © Paul Weisflog.
Is our chair steady? © Paul Weisflog.
Frame and chair, © Paul Weisflog.
Assembling of the Sanctorian chair, © Paul Weisflog.
Lifting the counterweight to enable a student to enter the chair, © Paul Weisflog.
Determining the descent of the chair in a balanced position, © Paul Weisflog.
Determining the descent of the chair, © Paul Weisflog.
Determining the position(s) of the counterweight, © Paul Weisflog.
Adapting the suspension of the chair to increase its stability, © Paul Weisflog.
Further adapting the suspension of the chair to increase its stability, © Paul Weisflog.
Fixed wood panel behind the chair to increase its stability, © Paul Weisflog.
Modern solution of a ball bearing as suspension of the chair, © Paul Weisflog.
Solution for the suspension of the chair, © Paul Weisflog.
Further measurements, © Paul Weisflog.
Balancing the chair, © Paul Weisflog.
