Here is an answer to the question posed in the blog on 29 June. Despite the detailed description I am still not quite sure why it would be needed. Normally indicator diagrams are used to determine power output but this one seems to require a dynamometer to verify it! At least we know what it is and that once again I have proved to be wrong - my motto is: often in error but never in doubt. The other snippets are also of interest as they show that in 1926 crash helmet design was quite advanced and chromium plating was being advocated.
JdK"...I still don't know what this thing does exactly!"
