44 The N.Z. Journal of Science and Technology. [Jan. 
steel works of that country, the author remaining in New Zealand, and, as 
opportunity offered during the years 1900 to 1908, carrying on experi¬ 
ments. 
Commencing with a study from all available sources of the problem of 
the reduction of iron-ores, the opinion was formed that the treatment of 
ironsand presented no chemical or thermal difficulties very different from 
other ores, and that the essential difference lay in the physical form of the 
ore ; and a deliberate attempt was made to produce, on a small scale, a 
furnace which on a large scale might be expected to smelt the sand com¬ 
mercially. It was early decided to adopt the use of powdered coal, for 
' the following reasons : (1) The raw sand is in a pulverized condition : 
(2) raw coal is the cheapest source of thermal energy ; (3) New Zealand 
contains much coal suitable for pulverizing, which can be obtained at a 
low price. 
All the furnace work was carried out in Christchurch. A ton of sand 
was obtained from New Plymouth, a small gas-engine, Roots blower, 
crushing-machine for coal, and the magnetic separator and dynamo used 
in the gold-mining experiments were installed. The first furnace built is 
shown in fig. 1. The furnace comprised a conical hopper A, combustion- 
chamber B, vertically over a plumbago crucible heated by a coke fire C. 
The furnace-gases, leaving by flue D, heated up the air blown in through 
pipe E. 
To start the furnace the chamber B had a temporary fire of coke put 
in it and blown up till the interior of the brickwork was up to a red heat, 
when the coke was removed, the hopper put in position, and feeding of 
the charge commenced. The charge consisted of a mixture of powdered 
coal and ironsand, which was caused to flow from the bottom of the 
hopper by the vertical reciprocation of a small plunger at the bottom of 
the hopper. Westport and Kaitangata coals were tried; a small parcel 
was also procured from the Paparoa property, which was at this time in 
the early stages of development. Lime was fed in with the charge as a 
flux. By strenuous labour the firing with the powdered coal was accom- 
