occasioned by mechanical means.
The laboratory form in common use consists of a bellows worked by either
hand or foot, and a special type of gas burner formed of two concentric
tubes, one conveying the blast, the other the gas; the supply of air and
gas being regulated by stopcocks. The _hot blast blowpipe_ of T.
Fletcher, in which the blast is heated by passing through a copper coil
heated by a separate burner, is only of service when a pointed flame of
a fairly high temperature is required. Blowpipes in which oxygen is used
as the blast have been manufactured by Fletcher, Russell & Co., and have
proved of great service in conducting fusions which require a
temperature above that yielded by the air-blowpipe.

For the applications of the blowpipe in chemical analysis see
CHEMISTRY: _Analytical_.

BLUCHER, GEBHARD LEBERECHT VON (1742-1819), Prussian general field
marshal, prince of Wahlstadt in Silesia, was born at Rostock on the 16th
of December 1742. In his fourteenth year he entered the service of
Sweden, and in the Pomeranian campaign of 1760 he was taken prisoner by
the Prussians. He was persuaded by his captors to enter the Prussian
service. He took part in the later battles of the Seven Years' War, and
as a hussar officer gained much experience of light cavalry work. In
peace, however, his ardent spirit led him into excesses of all kinds,
and being passed over for promotion he sent in his resignation, to which
Frederick replied, "Captain Blucher can take himself to the devil"
(1773). He now settled down to farming, and in fifteen years he had
acquired an honourable independence. But he was unable to return to the
army until after the death of Frederick the Great. He was then
reinstated as major in his old regiment, the Red Hussars. He took part
in the expedition to Holland in 1787, and in the following year became
lieutenant-colonel. In 1789 he received the order _pour le merite_, and
in 1794 he became colonel of the Red Hussars. In 1793 and 1794 he
distinguished himself in cavalry actions against the French, and for his
success at Kirrweiler he was made a major-general. In 1801 he was
promoted lieutenant-general.

He was one of the leaders of the war party in Prussia in 1805-1806, and
served as a cavalry general in the disastrous campaign of the latter
year. At Auerstadt Blucher repeatedly charged at the head of the
Prussian cavalry, but without success. In the retreat of the broken
armies he command