The Finnish Sauna

I've read through John Virtanen's 1974 book The Finnish Sauna: Peace of Mind, Body, and Soul.  This is the oldest sauna book I have seen.  The chapter organization seems a little disjointed and the book itself seems a collection of information that could benefit from the attention of a good editor.  It begins with a semi-autobiographical story of his youth and saunas in Finland, moves to a description of the historical role of saunas, and ends with descriptions of the current place of saunas in society and provides some practical construction details.  His recommendations for a "typical wall section" appear much the same as one would see today. 

The author appears to be promoting quality designed electric saunas as the safest and most affordable type.  Virtanen cautions about poisonous charcoal fumes or propane fumes from poorly operated or designed saunas of either type, and criticizes ineffectively designed electric stoves as well.  Otherwise, he has many good things to say about the traditional wood heated sauna.  Describing saunas in Siberia he writes "Log saunas throughout Russia are built of timber... a flat roof is made of turf over the round timbers."  This reminds me of Alvar Aalto's sauna I encountered earlier while reading Nordskog's book.  On page 125 is pictured an old shed roofed log sauna on the Karelian Isthmus that could easily be mistaken as a prototype for Aalto's design. The many black and white photos and pictures throughout the book are one of its best attributes. 

Virtanen states a humidity of 1.20 ounces of water vapor by weight per pound of air is the technical suggestion, but offers a simple rule of thumb that anyone can gauge, somewhere between "dry" and "steamy" is best [183].  He later writes [205]:

The main requirement of the Finnish sauna is that it create bathing conditions which cause the bather to perspire freely.  These conditions include the regulation of temperature, humidity and ventilation... The sauna should have an invigorating, rejuvenating, and tempering effect, while cleansing the body, refreshing the spirit and giving the feeling of complete well-being which is always the result of a good sauna.