ADDRESS. 21 
properties of the manganese alloys, according to their richness in that 
metal, are also shared by the nickel alloys, some of which possess 
very valuable properties; thus, it has been shown by Riley that a 
particular variety of nickel-steel presents to the engineer the means 
of nearly doubling boiler-pressures, without increasing weight or dimen- 
sions. He has, moreover, found the co-existence of manganese in small 
quantity with nickel in the alloy to contribute importantly to the deve- 
lopment of valuable characteristics. 
The careful study of the alloys of aluminium, chromium, manganese, 
_ tungsten, copper, and nickel, with iron and with steel, so far as it has 
been carried, with especial reference to the influence which they respec- 
_ tively exercise upon the salient physical properties of those materials, 
even when present in them in only very small proportions, has demon- 
_ strated the importance of a more searching or complete application of 
chemical analysis, than hitherto practised, to the determination of the 
composition of the varieties of steel which practical experience has shown 
_to be peculiarly adapted to particular uses. It appears, indeed, not im- 
probable that certain properties of these, hitherto ascribed to slight 
variations in the proportion or the condition of the constituent carbon, or in 
the amounts of silicium, phosphorus, and manganese which they contain, 
may sometimes have been due to the presence in minute quantities of 
one or other of such metals as those named, and to their influence, 
either direct or indirect, in modifying or counteracting the effects of 
the normal constituents of steel. The important part now played by 
manganese in steel manufacture is an illustration of the comparatively 
recent results of research, and of practical work based on research, 
in these directions, and the effects of the presence in steel of only very 
small quantities of some of the other metals named are already, as I 
have pointed out, being similarly understood and utilised. 
Such systematic researches as those upon which Osmond, Roberts- 
_ Austen, and many other workers have been for some time past engaged, 
“may make us acquainted with the laws which govern the modifica- 
tions effected in the physical characteristics of metals by alloying these 
with small proportions of other metals. The suggestion of Roberts- 
Austen, that such modifications may have direct connection with the 
periodic law of Mendeleeff, explaining the causes of specific variations 
in the properties of iron and steel, has been followed up energetically 
‘by Osmond, who has experimentally investigated the thermal influence 
upon iron of the elements phosphorus, sulphur, arsenic, boron, silicium, 
nickel, manganese, chromium, copper, and tungsten. He regards his 
results as being quite confirmatory of the soundness of Roberts-Austen’s 
Suggestion, as they demonstrate that foreign elements having atomic 
volumes lower than iron tend to make it assume or preserve the particular 
molecular form in which it has itself the lowest atomic volume, while the 
_ tonverse is the case for the foreign elements of high atomic volume. 
