Copyright
D. Peirce.

Observer and record of agriculture, Science and art (Volume v.1) online

. (page 9 of 35)
Online LibraryD. PeirceObserver and record of agriculture, Science and art (Volume v.1) → online text (page 9 of 35)
Font size
QR-code for this ebook


42



REMARKS ON THE PRESERVATION OF TIMBER.



Vitriol, 2. Spirit of minder., 2. Tar-
tar solub., 2. Sal. diuret., 2. Sal. am-
moniac, 3. Saline mixture, 3. Nitre 4.
Salt of hartshorn, 4. Salt of wormwood,
4. Borax, 12. Salt of amber, 20. Al-
um, 30.

Besides these there are various substan-
ces which possess in a high degree, ajiti-
ceptic properties, among them camphor
ranks very high,

Aqua Regia, A combination of nitric
and muriatic acids.

In the new nomenclature, it is called
nitro-muriatic acid; it is called aqua regia,
as the only acid formerly known to dis-
solve gold.

Aqua Secunda, Aqua-fortis diluted
with water, and employed in the arts.

Atom, In Philosophy, a particle of
matter so minute as to admit of no division.



REMARKS ON THE PRESERVATION OP
TIMBER.

The following methods are reccomend-
ed for the purpose:

1st. To girdle the tree by cutting away
a ring of the alburnum, in the early part of
summer, thus putting a stop to the further
ascent of the sap, and then to sufTer' it to
stand until the leaves should have expend-
ed, by their growth or transpiration, all
the fluid which could be extracted by them
previously to the death of the tree. The
wood would thus, probably be found in
the driest state, to which any treatment
could reduce it in the living state.

2nd, Strip the tree of its bark in the
spring, and fell it in ^the succeeding au-
tumn.

3d, Consists in immersing the green
limber in clear water for about two weeks,
after which it is taken out and seasoned
in the usual manner. A great part of the
sap, together with the soluble and ferment-
able matter, is said to be dissolved or re-
moved by this process. Running water
is more effectual, than that which is stag-
nant. It is necessary that the timber
should be sunk, so as to be completely un-
der the water, since nothing is more de-
structive to wood than partial immersion.
4th, The sap to be extracted by an air
pump.

5th, The but-end of the trees to be placed
in water, with the branches and leaves on



them, the water will displace the sap;
seasoning afterwards removes the water.

Gth, Pyro-ligneous acid, tar, bitumen,
and other resinous substances; or lime in
powder, or mixed with water, or other
fluid; common salt, (muriate of soda,) de-
prived of its bitter deliquescent salts,
(which substance is said to cause damp-
ness in sea vessels;) nitre, alum, and some
of the metallic salts, such as sulphates of
iron, copper, and zinc. Wood, boiled in
a solution of the former of these metals,
and afterwards kept some days in a warm
place to dry, is said to be impervious to
moisture. Oxide of iron combined with
an antiseptic fluid, and forced into the
spongioles of the wood; or a fluid of this
character, maybe combined with any an-
tiseptic finely pulverized solid substance,
and forced in the same manner by hy-
darulic or other pressure, into the spongi-
oles of the wood. Corrosive sublimate
is also recommended.

(See article page 6, on this subject.)

ON A METHOD OF DRAWING EXTREMELY

FINE WIRES.

By W. H. Wollaston, M. O. F. R. S.

Artists who use silver wire in large
quantities, sometimes begin with a rod 3
inches in diameter, and ultimately obtain
wires of no more than -^\-^ of an inch in
thickness. If in any stage of this pro-
cess a hole be drilled longitudinally
through the silver rod, having its diame-
ter one-tenth of that of the rod, and if a
wire of pure gold be inserted so as to fill
the hole, it is evident that by continuing
to draw the rod, the gold within it will be
reduced in diameter, exactly in the same
proportion as the silver; so that if both be
thus drawn out together till the diameter
of the silver is -^\-^ of an inch, then that
of the gold will be only -j-^'po, and of such
a wire, five hundred and fifty feet will
weigh no more than one grain. Now, if
such silvered gold wire be steeped for a
few minutes in warm nitrous acid, the sil-
ver alone will be dissolved, and the gold
will be left untouched. In this way
the author succeeded in making gold
wire of very great tenuity, but he expe-
rienced great difficulty in drilling the hole
in the silver rod and inserting the gold.
He therefore made the experiment of sub-
stituting platina for gold wire, as its infu-



ON THE BAROMETER.



43



sibility would then allow the silver to be
poured round it in a fluid state, without
injuring the texture of the platina.

A cylindrical mould of tlie third of an
inch in diameter was made; in the centre
of which, wa sfixed a platina wire -j^^ of
an inch in diameter, and the intervening
space was filled with melted silver. When
this rod was drawn to j^ the platina
which it contained in its centre was reduc-
ed to y^^^oj ^"^1 by a successive reduction,
and application of nitrous acid to dissolve
away the external coat of silver, platina
wires of ^j^Vo' ^"*^^ r^iv were obtained
which are very useful for applying to eye
pieces of astronomical instruments, and
are as fine as can be required for such pur-
poses, since in a thirty inch telescope,
TToa °^ ^" ^"



Online LibraryD. PeirceObserver and record of agriculture, Science and art (Volume v.1) → online text (page 9 of 35)