What is this skip-tooth bike?
This era of bicycle is especially hard to pin, it could be a Elgin, Hawthorne/Wards, Phillips, an Iver Johnson or many others that were making similar bikes. Do the pedals have any words on them embossed in the plastic? 

If i had to guess i would agree that it is a Pre-WWII as other have said probably around mid to late 30's. Many frames back then had the dual top tubes however many had a bend in the upper one and a "gas tank" in between them. I assume there is not head badge or any other kind of markings? If original the hub and components may lend some information but it is difficult to say from this era. 

The saddle was likely a dual rear spring leather "brooks" style saddle that looked something like the one seen on this Iver Johnson: