i88o.] 
New Scientific Processes and Inventions < 
47 
Prof Barff’s method is to subjeffi the manufactured article to 
the action of superheated steam in a sort of oven chamber or 
muffle and he states that one of the conditions of success is 
that the steam shall be perfefflly dry, and another that atmo- 
spheric air be excluded. In his earlier experiments it was often 
found that the black oxide scaled off wrought-iron articles, and 
this is attributed to an insufficient and irregular supply of steam 
allow ng adm ittan ce of air. The presence of moisture is pre- 
vented S by comnletely superheating the steam which is raised 
to a temperature of about 900“ F. for wrought-iron and steel, 
and from iooo 0 to 1500° for cast-iron. After describing a 
lot struggle with the difficulties which presented them- 
cplves subsequently to obtaining the original patent, Professor 
Bmff told the So cfety of Arts, on the ,6th of March last, that 
These laborious and costly experiments “have resulted in my 
, • able to state that my process is now commercially perfecft, 
being abletostate tn 1 y V gentlemen in the iron trade to 
rdltTn and use It ’’ From the prospectus of The Rustless 
and General Iron Company it appears that this has been done. 
The properties of the artificial surface of magnetic oxide 
which is thus obtained are — 
1 The durability of a stable compound not liable to oxidation, 
nor to the action of ordinary corrosive agents. Prof. 
Barff has published a number of testimonials from manu- 
facturers and others, who have tested the coating very 
severely by exposure to weather, to sea water, to alterna- 
tions of temperature, as in cooking-vessels, &c. 
2 The appearance is agreeable, and has the metallic charaaer 
of iron, but of darker colour. It is totally different 
from any paint. 
, It gives great hardness. Prof. Barff states that when one- 
3 ' sfxteenth of an inch thick or less “ an ordinary flat rasp 
wUl not remove it without great labour ; it resists emery 
powder. 
. “ Substances which adhere to iron, zinc, and enamel will 
4 ‘ t arlKere to it Saucepans in whicn arrowroot and 
other stfa^substances Jo cooked can be cleaned with 
the greatest ease, after they have been oxidised, a simple 
wine removing all dirt.” Water was “ evaporated in an 
oxidised pan for six weeks— common tap water ; the de- 
posit found was removed with a duster ; it did not Stic 
to the iron.” 
C “Articles coated can be submitted to a high temperature, 
5 ' fven a red-heat, without the coating being injured or d.s- 
turbed.” 
6. “ The process tightens the rivets, and assists in caulking 
rivetted iron plates.” 
