Rarefaction and condensation by instruments were also tried, but in vain.

Also, rarefaction by the air-pump does not injure air in the least degree.

With these pumps a higher degree of rarefaction can be obtained.

Waves: transverse, longitudinal; wave length, condensation, rarefaction.

Indicate the parts of the curve that correspond to a condensation and to a rarefaction.

He said that things are produced from air by rarefaction and condensation.

The rarefaction of the air and the scanty pasturage were the worst troubles.

This is precisely what is meant by rarefaction and condensation.

My ears also ached exceedingly in consequence of the rarefaction of the atmosphere.

He tries the rarefaction of air, but finds the effect insensible.