Typically they are steam pumps, the steam and water cylinders being set tandem on the same bed frame, generally without fly-wheel or other rotary parts; they may be single cylinder or duplex, simple, compound or triple expansion, and having a higher speed of stroke are smaller in all their parts than Cornish pumps.
Duplex has hose-in-hose flowers.
Grubb's duplex micrometer is described in the 9th edition of the Encyclopaedia Britannica.
The first to introduce a really good practical system of duplex telegraphy, in which this difficulty was sufficiently overcome for land line purposes, was J.
It was due to their specific qualities, and to the diverse circumstances of their external development, that the re-birth of Europe took this form of duplex action on the lines of intellectual and moral progress, followed by reaction against mental freedom.