156 = Lieut. Baddeley on the geognosy. 
of Werner and Gibbs, this oxide of iron is not magnetic while 
remaining at a considerable depth below the surface of the earth, 
but soon acquires this property after exposure to air and light.” 
We must seek other causes to account for the magnetic defici- 
ency in the present instance, as the specimens in question were 
taken from the surface and possess no more magnetism at the 
presént moment than they did at first. It may be owing to one 
or more of the following causes ; the presence of oxygen above 
30 per cent, of sulphur above 40, of carbon, of phosphorus, 
of arsenic, of manganese and of antimony; of these sulphur, 
phosphorus, arsenic, manganese and antimony injure the ore, 
by either rendering it difficultly fusible or its cast-iron brittle, 
often both. Carbon, on the contrary, improves the quality of 
the cast-iron, renders the ore more easily fusible and diminishes 
the consumption of fuel, We cannot sayto which of these, 
or if to any of them is owing the magnetic deficiency, we can 
only observe that before the blowpipe no fumes of sulphur, arse- 
nic nor of antimony were perceived. From sixty to seventy 
per cent. of cast iron may be expected from the magnetic ores, 
and from thirty to forty from the bog ore. 
The vicinity of limestone as a flux bestows additional value 
on these deposites. It is probable that the limestone that was 
seen at the entrance into St. Paul’s Bay may extend thus far, 
We saw two or three varieties of an excellent description near 
a small kilo in front of the chapel at St. Urbain, which 
were said to have been taken from the bank on the opposite 
or left side of the river ; some contained organic remains, while 
others had more the aspect of a compact marble, and were 
free from them, We were informed that lime stone was also 
to be seen on the summit of the hill opposite the chapel, 
where indeed it was ultimately found, but our guide took us 
first to several felspathose rocks deceived by their whitened sur- 
faces. 
Wishing 
