Because it was rough time.
here are 5 methods: Issuing bonds,Sales of common stock, Issuing preferred stock,Borrowing or Using profits
Silk Road in Western Han Dynasty (206 BC–24 AD) From 139 BC to 129 BC, Zhang Qian set out on his journey to the Western Regions twice, pioneering the world-famous route.
Honestly, none. The union didn't really have any agricultural advantages over the Confederacy, in fact, it can be argued that agriculture was one of the biggest disadvantages of the union.
