silicium, graphite, manganese, and combined carbon reduce the elasticity,
strength, and tenacity of cast iron, and that a limited percentage of
silicium counteracts the injurious influence produced by an excess of
combined carbon. On remelting of cast iron, increase in tensile strength
was observed, which attained its maximum in iron with a small percentage
of silicium after the third, and in such with a large amount after the
fourth melting. The increase in tensile strength was accompanied by a
loss of silicium, graphite, and manganese coupled with a simultaneous
augmentation of combined carbon. A fifth melting of the cast iron renders
it hard, brittle, and white, through oxidation of silicium and subsequent
lowering of the amount of carbon. On lessening the percentage of combined
carbon with formation of graphite the injurious influence of the
accessorial constituents of cast iron is diminished, especially that
produced by the presence of phosphorus.--_Eisenhuettentechnik._

* * * * *




FEEDING BOILERS AT THE BOTTOM.


One of the most important things to be considered in boiler construction
is the position and arrangement of the feed apparatus, but it is,
unfortunately, one of the elements that is most often overlooked, or, if
considered at all, only in a very superficial manner. Many seem to think
that it is only necessary to have a hole somewhere in the boiler--no
matter what part--through which water may be pumped, and we have all that
is desired. This is a very grave error. Many boilers have been ruined,