And there was an enlarging, and a winding about still upward to the side chambers: for the winding about of the house went still upward round about the house: therefore the breadth of the house was still upward, and so increased from the lowest chamber to the highest by the midst.
The breadth of the house was still upward, and so increased from the lowest chamber to the highest -
i.e., the breadth of the internal space above was greater than that below.
By the midst - through the middle.