Where’s the Dipstick?

I recently visited a working farm and had the pleasure of seeing a number of old farm tractors that, in spite of their age, were still pulling their weight and significantly more. One of the more intriguing tractors was the one to the right. When asked when this tractor last ran, I was told to sit in the seat, shake the shifter to make sure it was not in gear, pull out the knob on a steel plate, and advance the throttle a bit. The farmer than turned a petcock to open a gas line and engaged a crank in the front of the engine. After giving it only one hard crank, the engine came to life and was purring like a kitten; no smoke, knocking, pinging, clicking, clacking, spitting or sputtering. And after a short ride in the field, it was clear that this was, aside from its age and rusty appearance, a well-maintained machine that was built to last.

The next interesting experience came when I asked how to check the oil in the tractor below, since, for the life of me, I could not figure it out. Whereas I was schooled on the basics of vintage tractors when he showed me how to check the oil, I wonder how many in our industry would know.

How do you check the oil level in this tractor? As a bonus, what type of oil do you think is used in this tractor and the one that he cranked to start?