I get a bit confused about the meaning of the preposition by in 'by the other side' in the context below. Could you help to explain it for me in detail?
The Rat got hold of an oar and shoved it under the Mole's arm;then he did the same by the other side of him and, hauled him out...
— The Wind in the Willows, Kenneth Grahame (1859–1932), pub 1908
In addition, I have searched the meaning of by in Longman's dictionary and it comes out with many different meaning. My problem is I am not sure which meaning it should be in the situation of my case.