|1919 Ford Model T fitted with a Virgil White Snowmobile conversion.|
Reading The River of Doubt by Candice Millard, I came across this passage on page 94:
On January 25, some good news arrived for Roosevelt and his men in the almost surreal form of three huge all-terrain trucks. The "auto vans," as Zahm called them, rattled into camp that night on their way to the Utiarity telegraph station, the expedition's next stop, and the point at which it would turn west and head directly toward the River of Doubt. The trucks, which belonged to the Rondon Commission, each carried two tons of freight and had been outfitted with wide, slatted belts that wrapped around the wheels on each side like tank treads, forming what Miller referred to as an "endless trail" through the thick mud. This invention, which anticipated the use of the first military tanks two years later, during World War I, amazed and elated the explorers. "It was strange to see them racing across the uninhabited chapado at a speed of thirty miles an hour," Miller wrote. "Surely this was exploring de luxe."That would be January 25, 1914. Although it seems highly improbable that tracked vehicles were operating in the wilds of Brazil way back then, I suppose it is possible. And while this Model T is not capable of carrying two tons of anything, it at least shows that the military weren't the only ones were building tracked vehicles.
P.S. Found the photo on Bring A Trailer. Lots of interesting stuff there.