As the curtain approached, the compass needle always deviated to the west, oscillated as the curtain passed the zenith, and then deviated to the east.
On the 15th of March it was of the fourth magnitude; during the next three months it oscillated many times between magnitudes 4 and 6, and by the end of the year it had faded to the seventh magnitude.
Longfellow's genius, in its choice of subjects, always oscillated between America and Europe, between the colonial period of American history and the Middle and Romantic Ages of European feeling.
After the victories of Pompey, however, the Romans claimed the suzerainty, so that, during the next decades and the expeditions of Crassus and Antony, they oscillated between Rome and Parthia, though their inclination was generally to the latter.
In this case the large vibrating mirror must be oscillated by a current from an alternator, on the shaft of which is a disk of nonconducting material with brass slips let into it and so arranged with contact brushes that in each period of the alternator a contact is made, charging say a condenser and discharging it through the oscillograph.