remedied, thanks being largely due to those engineers who have the
skill to suggest improvements and the patience to carry them out
against much opposition.

These improvements in many instances pertain to the engine builder's
duties, and are questions which I think have been treated lightly;
notably that of insufficient bearing surface, and one of the principal
causes of hot bearings, whereby the oil intended for lubrication was
squeezed out, and the metal surfaces brought too close in contact; and
when bearings had a pressure of 200 lb. per square inch, it has been
found that not more than 120 lb. per square inch should be exerted to
keep them cool (this varies according to the material of which the
bearing is composed), without having to use sea water and prevent them
being ground down, and thus getting out of line. I have known a
bearing in a new steamer, in spite of many gallons of oil wasted on
it, wear down one-eighth of an inch in a voyage of only 6,000 miles,
from insufficiency of bearing surface.

Several good rules are in use governing the strength of shafts, which
treat of the diameter of the bearings only and angles of the cranks;
and the engine builder, along with the ship owner, has been chary of
increasing the surfaces by lengthening the bearings; for to do this
means increase of space taken up fore and aft the vessel, besides
additional weight of engine. Engine builders all aim in competing to
put their engines in less space than their rivals, giving same power
and sometimes more. I think, however, this inducement is now more
carefully considered, as it has been found more economical to give
larger bearing surfaces than to have steamers lying in port, refitting
a crank shaft, along with the consequences of heavy bills for salvage
and repairs, also the risk of losing the steamer altogether.