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

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two are then made fast at the base of the
cog or tooth, and a mark made with pen
and ink on the wheel or pattern, at the
base of each tooth, opposite to the re-
spective marks or divisions on the wire.
The wire is then moved round equal to
the thickness of a tooth and the space
between two; and another tooth laid off,
or marked from base to end, as the one
before described, and in like manner all
the teeth which are of tliat character.
These are convex involute spin' teeth.

2. When teeth are formed upon a
concave surface, they are to be concave
involutes, formed from a circle at the
ends of the teeth.

3. In a straight rack the acting faces
of the teeth are parallel with each other,
and at right angles to its motion.

4. Face wheels have tiie faces of
teeth parallel with the axis of the wheel.

Bevil wheels, wilh teeth on the con-
vex surface, are a modification of spur-
wheels already described, and are laid off
on the same principle, one being on the
surface of a cylinder, and the other on
the surface of the frustum of a cone: the
teeth may be laid off upon one end, or
both, whichever may be most convenient;
care should be observed to have the
acting sides of the teeth in the same planes
as the axis of the wheel. When they
are laid off from one side, the large end
of the fr-jstum of the cone is to be
preferred, and the base, sides, and
ends of the teeth, be formed of straight
lines pointing toward the apex of the
cone. These are convex involute bevil
teeth ; and those upon the interior sur-
face of the frustum of a cone also, are
composed of straight lines, pointing to-
ward the apex of the cone, and are con-
cave involute bevil teeth.

Those upon the exterior and interior
surface of a cylinder, have the acting
faces composed of straight lines parallel
with the axis of the wheel. Face wheels
have the teeth made convex, in the line



of the wheel's motion, in proportion to
the diameter of the wheel into which it
is to work, or be engaged, and the teeth
on the interior or concave surface of a
rack, are made similar to those on the
interior surface of a cylinder of the same
curve; and those upon the exterior (or
convex) surface of a circular rack, are to
be made similar to those on the exterior
convex wheel of the same curve. A
sm.all flexible thread, or a rigid straight
edge, with a point or scriber attached,
may also be used to trace the involute
curves upon the edges of the teeth ; but
as the thread is liable to stretch, and
there is some difficulty in preventing
the straight edge from sliding upon the
circumference of the wheel, the wire is
preferable.

It appears to the writer of this, that
the teeth of wheels and racks, made upon
the principles here described, will fulfil
the aforesaid conditions, better than
where the acting sides or faces are com-
posed of epicycloidal, cycloidal, or con-
centric circular curves, or any part of
either; and that the involute can be con-
structed as rigorously correct as either;
and with as little labor. E. 0. R.



FLAME OF HYDROGEN RENDERED
LUMINOUS,

Dr. Hare, of Philadelphia, has render-
ed the flame of hydrogen luminous, like
that of oil, by adding a small quantity of
oil of turpentine to the usual mixture for
generating that gas. The light seems
greater than that of carburetted hydrogen.
He found also that the addition of l-17th
of oil of turpentine to alcohol gives this
fluid the property of burning with a
highly luniinous flame, and there is a
certain point in the proportions when the
mixture burns without smoke like a gas
light. — Reg. of virts and Sciences.



PRESERVATION OF FRUITS BY CARBONIC
ACID GAS.

Cherries, grapes, pears, apples, and
chestnuts (and perhaps all other fruits,)
l^laced in glass vessels filled with this
gas, obtained from carbonate of lime by
sulphuric acid, are said to be preserved
without undergoing any change for a
long period. Cherries at the end of six



192



NOTICE TO SUBSCRIBERS.



weeks had the same appearance as when
preserved in brandy. — ib.



EMPLOYMENT OF MINERAL TAR, OR PY-
ROLIGNEOUS LIQUOR, FOR THE PRO
TECTION OF WALLS OF MASONRY OR
OF MITD.

When the walls are thoroughly dry, to-
wards the end of summer, (having pre-
viously been either newly builtor put into
a new state of thorough repair,) they are to
be coated over once, twice, or thrice with
the tar. The last coat, immediately
when put on, may be powdered with
sand ; and this when solidified, may be
white-washed.

In France, earthen walls, and the walls
of court yards, and terraces, are treated
in this manner, and so rendered of great
durability. Farmer'' s Register.



PREVENTION OF DRY ROT IN TIMBER.

The gas of the kreosote, (supposed
creosote,) procured from the distillation
of coal or vegetable tar, which, when
driven off in the shape of gas, will pene-
trate every part of the largest logs, and
render the wood almost as hard as iron;
so hard indeed, as not to be easily
worked. It is understood that in Bel-
glum they are using it as blocks for the
rail-roads. The worm, {teredo navalis)
as proved at Sheerness, will not touch it,
while pieces of the same wood, steeped.
in corrosive sublimate, sulphurous acid,
and other active solutions, were bored
through and through. ib.



TIME FOR SOWING- SEEDS OF DIFFERENT
KINDS.

As it is admitted that, the duly adjust-
ing the periods of sowing seeds for dif-
ferent kinds of crops, according to the
forwardness of the season is of great im-
portance in agriculture, and as the tem-
perature is far from being the same in
different seasons, at the same period of



the year, it is thought best to adopt the
budding and leafing of trees as a standard
for determining the most proper period.
The budding and leafing of the birch, is
said to be considered in Sweden as a di-
rectory for sowing barley, and it is record-
ed in the t^moritates ,/3cademico, ihat the
illustrious Linnaeus exhorted his coun-
trymen to observe with care what time
each tree expands its buds, as information
which might lead to the most useful pur-
poses. For tliese reasons the prudent
husbandman is advised to watch the bud-
ding of trees, and to collect from this
circumstance the proper time for sowing,
and to make the operations of nature a
calender for his own labors, and it is con-
tended that more favorable crops than
would otherwise be obtained will amply'
reward his diligence.



NOTICE TO SUBSCRIBERS.
A description of Witherow and Peirce's
Cycloidal Plough, will appear in a future
number.

This number completes the first year
of the Observer and Record of Jigricul-
ture, Science, and Art.

An alphabetical table of contents, or
index, accompanies the number; this
will enable each subscriber to have the
volume bound. Those who think pro-
per to leave their numbers with T. E.
Chapman, No. 74 North Fourth street,
can have them bound in a good substan-
tial manner, and at a moderate expense.

Subscribers for the second volume can
also have the first, either in numbers
alone, or bound.

Subscribers and Postmasters are most
respectfully requested to act as r gents for
the work.

See prospectus, for object, plan, and
terms.

The second volume will commence
early in October.

Editor.



CONTENTS OF NO. 12. VOL. I.

On Bleaching Silk, 177

Sir. H. Davy's Agricultural Chemistry, . 179
Definition of Terms. Letter J. . . . 182

On Smut in Wheat, Ib6

Remarks upon the Teeth or Cogs of Wheels, show-
ing the proper form to be given to their Act-
ing Sides or Faces, . . . . 1 89
Flame of Hydrogen Rendered Luminous, . 191



OF OBSERVER AND RECORD.

Preservation of Fruits by Carbonic Acid Gas, 191
Employment of Mineral Tar, or Pyroiigneous Li-
quor, for the Protection of Walls of Masonry

or of Mud 192

Prevention of Dry Rot in Timber, . . 192
Time for Sowing Seeds of different kinds, . 192
Notice to Subscribers, , . . . 1-2



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