OTHER PROPERTIES OF CAST IRON. 267 
criptions ofiron are, generally speaking, weaker, 
yet more ductile when exposed to heavy strains. 
They are also better adapted to those objects 
where the finer outlines and free working pro- 
perties of the metals are required. 
In forming a judgment of the quality of a par- 
ticular iron, there cannot, however, be any great 
risk, as we have only to look into the following 
table of collected results, and there will be found 
thestrengthas wellastheother properties of each. 
If, for instance, a strong compact iron was want- 
ed, we have then to look for the number at the 
head of the list, and from 1 downwards to 15 
will be found to partake of that character.— 
Again, suppose a moderately strong yet fluid 
iron was required, the numbers 16 down to 26 
or 28, will more or less correspond with those 
qualifications. The same may be said of the 
lower numbers, all of which are a fluid and easy 
working class: they are admirably adapted for 
the finer descriptions of castings, when strength 
is not reqnired, and must ever be in demand 
where that object is not considered of impor- 
tance. In all these cases, it must however be 
admitted, that, much depends upon using an 
appropriate mixture, and by judicious combina- 
