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A NEW SOURCE OE IRON. 
The iron-sand which covers manv miles of the country in 
the neighbourhood of New Plymouth, New Zealand, has 
been ascertained to consist of the peroxide of iron, with 12 
per cent, of titanium—a rare combination. The finest cast- 
steel is made directly from this titaniferous iron-ore; and 
sundry cutting instruments, such as razor-blades, knives, 
&c., having been formed from it, they have been found to 
possess much hardness, a keen edge, and not to tarnish 
quickly. 
There can be no questioning the value of this sand to the 
colonists, whilst the supply is said to be almost inexhaustible. 
CONVERSION OF CAST-IRON INTO PLUMBAGO. 
At a recent meeting of the Royal Society, Professor Crace- 
Calvert announced an interesting chemical discovery—that 
cast-iron is convertible into plumbago. The professor soaks 
cubes of cast-iron in weak acid—vinegar being the most 
suitable—until the iron is dissolved out, and the carbon 
remains. By this process the cubes lose in weight, but not 
in dimensions, and retain their form unaltered; but the 
quality is changed, and it is as easy to draw lines with one 
of them as with a lump of plumbago. Artists and others 
who have been uneasy as to failure in the supply of lead for 
pencils, may now dismiss their apprehensions; for, while 
cast-iron is to be had, the desired material will be available. 
Strictly speaking, it is not carbon, but a cyanide of carbon, 
which remains after the solution of the iron. 
ANALYSIS OF THE AIR. 
Dr. Fkankland has analysed air from Mont Blanc, at 
an altitude of 11,000 feet, and finds it to consist of— 
Nitrogen ..... 79-05G 
Oxygen ..... 20 881 
Carbonic acid .... '0G3 
100-000 
Dr. Miller examined air collected during a balloon-ascent at 
a height of 18,000 feet, and found 20 88 per cent, of oxygen; 
whilst a sample of air collected at the same time near the 
