2 collocations for rarefies

"'The heat of the sun occasions the trade-winds, by rarefying the air at the equator, which causes the cooler and more dense part of the atmosphere to rush along the surface of the earth to the equator, while that which is heated is carried along the higher strata to the poles, forming two currents in the direction of the meridian.

But in the society to which the boy belonged by his gentle manners and his trick of speech, which could only come as a birthrightin that rarefied world where the ladies wore low gowns, with diamonds around their necks, and the gentlemen dined in fine linen with wide shirt-frontsall life moved upon the machinery of romance.

2 collocations for  rarefies