The first doesn't make much sense to me as the meaning for 'macadamised' that I know is to do with road building. (http://en.wikipedia.org/wiki/Macadam)
The second is just a lively description of the effects of a gas leak.
A dumbwaiter is a lift for food or a portable table for serving food. I'm not quite sure how this works with slipping off its trolley, but think it is more likely to be the lift, which is stable enough to stay in the correct position.
3. What does 'macadamized lounge' mean? (He would remove his coat and, sit upon a macadamized longue and read.)
In addition, a macadamized road is a gravel road. As for 'macadamized lounge', the author uses the adjective 'macadamized' to describe the lounge chair's level of comfort: sitting in that particular chair is comparable to sitting on a pile of gravel.