well, refering to the original post, we are talking about white pine aren't we?? and i can assume that the white pine 80 years ago is fairly high grade lumber compaired to what we are using now. and i can also assume that the guy on the working end of the broad axe or adze is cutting to dimensional sizes not nominal.
as far as the design loads are concerned... if he is planning on parking a grand piano,or a car on the floor it is probably not adequate. however (with typical live loads) as long as the flooring material and the primary carrying members are sized properly, a 6x6x8' timber spaced as close to 30" as possible should be about right.
the only reason why i refered to steve's book is that brad probably recieved it while standing in a building at fox maple that was framed that way. steve is one person that i know of that frames floor joists this way, and his book is a viable resourse.
