The “first real” tractor wasn’t invented in 1839 (that one wasn’t self-propelled, it was just a movable steam engine). The first actual self-propelled traction engine was produced in 1859, and obviously many traction engine-related inventions followed in the next couple of decades.
The plough page you linked earlier mentions several different kinds of ploughs being invented around 1873 – for example the stump-jump plough which was invented in 1876. It’s entirely possible that there was some kind of plough invented in 1873.
However, the most likely explanation is probably this: John Deere created the first steel plough in 1837. The author of this meme found this fact and mistakenly swapped the 3 and 7 around, arriving at 1873.
The “first real” tractor wasn’t invented in 1839 (that one wasn’t self-propelled, it was just a movable steam engine). The first actual self-propelled traction engine was produced in 1859, and obviously many traction engine-related inventions followed in the next couple of decades.
The plough page you linked earlier mentions several different kinds of ploughs being invented around 1873 – for example the stump-jump plough which was invented in 1876. It’s entirely possible that there was some kind of plough invented in 1873.
However, the most likely explanation is probably this: John Deere created the first steel plough in 1837. The author of this meme found this fact and mistakenly swapped the 3 and 7 around, arriving at 1873.