Year: 1861

ture itself, if they had been deprived of the aid
of theoretic chemistryp


For example :--Aninc-frst discovered in
coal tar by Dr. Hoffman, who has so admirably
developed its properties--s now most exten- :
sively used as the basis of red, blue, violet and
green dyes. This important discovery will pro-
badly, in few years, render his country indie
pendent of the world for dye. .stufls and it is
more than probable tha, England, instead of
drawing her dye stuffs from foreign countries,
may herself become the centre from which all
the world will be supplied


1t is an interesting fact that nt the same time
in another branch of this SCIENCE NJ. Tournct
has lately demonstrated that the colors Of gems,
such as the emerald, aqua marina, amethyst,
smoked rock crystal and others, are due TO vol
atle hydro carbons, first noticed by Sir David
Brewster in clouded topaz, and that they are
not derived from metallic oxyds as has been
hitherto believed.


THE COMPOSITION OF STEEL.


In noticing the more recent discoveries in
this important science, must not pass over in
silence the valuable light which chemistry has
thrown upon the composition of iron and steel.
Although Despretz demonstrated many years
ago that iron would combine with nitrogen, vet
it was not until Sj7 that Mr.. G. Binks proved
that nitrogen is an essential element of steel,
and more recently NJ. Garon and NJ. Frenzy
have further elucidated this subject the fer
mer showing that cyanogen, or cyanide Of am
monium, is the essential element which converts
wrought iron into steel the latter combining
iron with nitrogen through the medium of am
monia. and then converting it into steel by
bringing it at the proper temperature into con-
tact with common coal gas. There is little doubt
that in few years these discoveries will enable
ma In ron hpir trp nj
uncertain, cumbrous, and expensive process, by
method at once simple and inexpensive, and
completely under control as to admit of any
required degree of conversion being obtained
with absolute certainty. Mr.. Grace Calvert has
also proved that cast iron contains nitrogen and
has shown that it is definite compound of car
bon and iron mixed with various proportions of
metellic iron, according to its nature.


IRON sHIpBUILDING.


In iron shipbuilding an immense field is open
ing before US. Our wooden walls have, to all
appearance, seen their last days and as one OF
the early pioneers in iron construction as ap-
piled to shipbuilding | am highly gratifcd TO
witness a change of opinion that augurs well for
the security of the liberties of the country.
From the commencement of iron shipbuilding
in 1880 to the present time, there could be on
" one opinion among those best acquaint ed
with the subject, namely, that iron must event
ualy supersede timber in every form of naval
construction. The large ocean steamers Him
alaya, the Persia, end the Great Eastern, abun-
dainty show what can be done with iron, and
we have only to look at the new system of cas-.
ing ships with armor plates to be convinced
that we can no longer build wooden vessels OF
war with safety TO our naval superiority and the
best interests of the country. | give no opin.
ion as to the detail of the reconstruction of the
navy-that is reserved for another place-bui
may state that am fully persuaded that the
whole of our ships Of war must be rebuilt o
iron, and defended with iron armor calculated
to resist projectiles of the heaviest description
at high veocities.