436 
gate when two-thirds of the power had 
been applied, and this became more and 
more sensible, apparently in a geometrical 
ratio with the arithmetical increment. The 
worst iron tried, gave way under the appli- 
cation of 14 tons to the square inch; and 
did not elongate materially before the burst: 
four bars of metal of a medium quality 
being forged together, an iron was obtained 
which did not begin.to lengthen until 16 
tons had been applied, supporting 24 tons 
weight, without breaking. 
These results being allowed as suffi- 
cient data, a committee, appointed for the 
purpose, decided that the thickness of 
chains in suspension bridges, should be so 
calculated, that the maximum weight 
should not exceed 8 tons per square inch of 
the sectional surface, and that, before use, 
they should be subjected to a proof-weight 
of 16 tons per square inch, bearing it without 
sensible elongation. 
Ancient Roman Gillass.— A fragment, 
which was disintegrated into thin plates 
to such a degree as to fall into smali leaves, 
like Mica, when broken, pressed, or scraped, 
has been analyzed by Dr. Rudolph Brandes, 
and found to contain silica, soda, oxide of 
lead, of manganese, and of iron, lime, and 
alumina. The silica formed about two- 
thirds of the mass; which had been so far 
acted upon, by water and other. agents, as 
to haye lost its transparency except towards 
the centre. The colour was milky white, 
with a blueish cast ; in some parts lustrous 
like gold. 
Psittacide. — Barron Field, Esq., late 
chief-judge in New South Wales, has made 
a beautiful addition to the Ornithology 
of Australia, which, in just acknowledg- 
ment, is called Psrrracus Fretpu. It 
is thus described :—general colour, green ; 
head chestnut-brown ; wings, beneath, 
black; under wing-covers cerulean blue ; 
tail rounded. In size rather larger than 
the Ceram Lery: bill comparatively thick 
and strong; upper mandible slightly sul- 
cated down the middle of the culmers ; 
under mandible longer than deep; gonix 
ascending ; tip thick and obtuse, as in the 
short-tailed parrots of the New World; 
under part obsoletely triangulated ; cere 
entirely naked, and nostrils very large and 
round: upper plumage of a rich changeable 
grass-green, in some lights tinged with gol- 
den yellow, and in others with brown; un- 
der plumage paler, and more inclined to 
yellow ; quills, on the outer surface, dark 
green, on the inner dusky black ; second and 
third slightly longer than first quill: tail, 
moderate length, and feathers ovately or 
obtusely painted; colour above, green; 
interior yellowish, which tint is predominant 
on the lower surface. The tarsi are black 
and short. 
Distance to which Sand and minutely- 
divided Mutter may be carried by Wind—On 
the morning of the 19th of January last, 
Spirit of Philosophical Discovery. 
[Dec. A, 
Mr. Forbes, on board the Clyde East- 
Indiaman, bound to London, in lat. 10°. 
40. N. and long. 27°. 41’. W., about 600 
miles from the coast of Afficd, ‘was sur- 
prised to find the sails’ covered with a 
brownish sand, the particlés of which, being 
examined by a microscope, “appeared! 'ex- 
tremely minute. At two P.M., 'the” same 
day, some of the sails being unbent, clouds 
of dust escaped from them on their flapping 
against the masts. During the night, the 
wind had blown fresh N.E. by E., and the 
nearest land to windward was that ‘part of 
the African coast lying between Cape de ~ 
Verd and the river Gambia. May not the 
seeds of many plants, found in remote and 
newly-formed islands, have been thus eon- 
veyed ? 
In France, Hottann, and Austria, the 
comb-makers and horn-turners use the clip- 
pings of horn and tortoise-shell skins for 
snuff-boxes, powder-horns, and other cu- 
rious and handsome toys. They first soften 
the material in boiling water, so as to be 
able to press it in iron moulds, and, by 
means of heat, form it into a mass. The 
degree of heat must be determined by ex- 
perience, but must be stronger for horn- 
clippings than for shell-skins: it must, 
however, not be too powerful, for fear of 
scorching the horn or shell; and care must 
be taken not to touch them, either with the 
fingers, or any animal or greasy substance, - - 
as that would prevent their perfect joining. 
Wooden implements should be used at the 
fire, or in conveying the horn or shell to the 
moulds. 
A patent, it is said, has been solicited on 
the part of T. Steele, Esq., M.A. of Mag- 
dalen College, Cambridge, for some very 
important improvements in the construc- 
tion and use of the Diving-Bell. This im- 
provement, we hear, particularly attaches 
to the descent of an engineer, who may re- 
main at any depth beneath the water, and un- 
incommoded by the pressure of condensed 
air, may work with increased safety and ef- 
fect, maintaining uninterrupted communica- 
tion with those above, by means of conyersa~ 
tion. Mr. S. has thus invented a plan which 
will effectually supersede the imperfect and 
insecure méthod of signals, made by repeat- 
ed strokes of ahammer. The same gentle- 
man has, by the employment. of optical 
principles, formed an instrument for the il- 
lumination of bodies under water ; and also 
has improved the method of detaching men 
from the bell. eRe 
Mr. W. H. James has also invented an 
improved apparatus for men obliged to. work 
under water. A hood or helmet is)fixed 
upon the shoulders, and rendered. air. and 
water-tight ; and a vessel of condensed, air 
is to be carried behind the man, whenee he 
is to inspire pure air, by means of valves to 
be worked bya lever, somewhat in the man- 
ner of the bellows of a bagpipe. goiter 
Smell of Hydrogen: Gas.Thisigas;\ob- 
tained 
