The paper seeks to explore the meanings attached to the sauna in eighteenth-century scholarly discussions concerning the character and physiology of Man. The aim is to explain the surprisingly frequent references in eighteenth-century scholarly writings. The sauna, it will be argued, was perceived by scholars as a 'living laboratory' where the physiological mechanisms determining spiritual and scientific abilities of men could be assessed and principles of political philosophy tested in an isolated environment.

In the Eighteenth Century, the age-old climate theory (presumption that the spirit and disposition of men varied depending on the climate and other physical surroundings) was put to the test of empirical method. The philosophers were looking for concrete evidence to understand how body and human senses responded to cold and heat. The results were extended to explain presumed differences in national character. "Mettez un homme dans un lieu chaud et enfermé", wrote Montesquieu, invoking thus a sauna-like space as a testing ground for his ideas concerning the effects of heat on the fibres and nerves of the human body which formed the basis for his political theory.

In the same vein, travellers to the northern countries – as well as philosophers who read their accounts – paid close attention to the practise of sauna. A great difference of temperature between the warmed rooms and the cold climate was considered an excellent circumstance for studying the physiological and spiritual constituents of men. Nordic scholars soon realised that the sauna could be utilised as a scientific resource, and ordinary custom of bathing was mobilised for systematic experimentation. Men and women of various ages were marched in; and the effects on their body temperature, length of their limbs and other ‘symptoms’ were closely monitored, measured, and transcribed into tables. For the northerners, the conclusions drawn from these experiments had also sensitive symbolic meanings, since the climate theories had traditionally articulated strong prejudices towards the scientific potential of the northern regions.

By examining the thoughts which the sauna evoked in eighteenth-century scholars and philosophers, this paper seeks also to explore the scientific practises of the Eighteenth Century and to shed light to the patriotic functions attached with empirical science.