opportunity was had to observe them.

* * * * *




GIRARD'S "PALIER GLISSANT."


The term "_palier glissant_," which does not admit of being very happily
translated into an English term of equal brevity, is the name given by
the inventor, Mr. Girard, to a frictionless support, or socket, designed
to sustain the axes of heavy wheels in machinery. Since it is a
contrivance deriving its efficacy from hydraulic pressure, it may,
without impropriety, be considered here. The friction of axles in their
supports is the occasion of a considerable loss of power in every
machine.

[Illustration]

The loss of power itself, though a real disadvantage, is nevertheless a
matter of secondary consequence compared with the attendant elevation
of temperature, which, were not means carefully provided for reducing
friction to the lowest point possible, might soon be so great as to
arrest the operation of the machine itself. It was stated in a public
lecture delivered in May, 1867, before the Scientific Association of
France, that, in a certain instance within the lecturer's knowledge, the
screw shaft of a French naval propeller became absolutely welded to its
support, though surrounded by the water of the sea, in consequence of