The helmet is often used by the illustrator to label characters. A helmet labeled “Cat” might be expected here. This is a subversion of that expectation by labeling the helmet “Helmet”.
I think the “joke” is that Heathcliff is wearing a helmet to protect himself from being shat and pissed upon. The bird is wanting to perform its duties on his head.
… what
The helmet is often used by the illustrator to label characters. A helmet labeled “Cat” might be expected here. This is a subversion of that expectation by labeling the helmet “Helmet”.
Oh, that is a surprisingly logical explanation. Neat.
I think the “joke” is that Heathcliff is wearing a helmet to protect himself from being shat and pissed upon. The bird is wanting to perform its duties on his head.
Or maybe the joke is an artist who isn’t confident in his drawing enough to not write HELMET.