The New York herald., 1851-08-29

nate - has already been shown for the tides at the
nronose' At future meeting, to present the dis
cussion of these tides to the association, and at
or esent refer to the tables and diagrams showing
the decomposition Of the curve Of observation, and
the agreement of the curve computed from the
elements with the curves of observations. The
average difference in the computed and observed
ordinates Is less than four hundredths of foot.
This paper was illustrated by diagrams showing
the tidal curves.
PLOUGH, BY PROF. C.. w. HACKLBY, OF CsLUM-
Prof II. stated that he had received, some
me nths since, a com municatien from committee
questing him to ascertain, if possible, the true
theoretic form of the mould board of the plough,
SO that it would offer the leas. resistance, and tho
roughly perform the work and to include, if it
could be done the notification suitable to produce
the pulverizatiOn of the soil.
Theory and experiment show that the angle of
inclination of the edge OF the share, viii 81 cuts of
the furrow slice from the bottom, to the direction
of the ploughs motion, and that OF the coulter,
which cuts of at the side to the horizon, are mat
ters of little Importance. The advantage Of in
clinipg them is, that they may act like saw to
two portions of the plough is uniform, and is the
chic resistance to the draught. However, the GO
neral wedge like form of the plough indie ates that
the greater its length, (snce the breadth is fixed
by the required breadth Of the furrow) the less the
resistance, because the angle of the wedge would
thus be rendered more acute.
Four feet is the utmost length that would be con-
of the field The longest Scotch pol CHS are not
more than feet 9inches, and the American ploughs
are much shorter. The share and mould board
form properly one continuous surfice. After the
furro slice is cut Off by tho coalter and front edge
of the share, (Which latter We may suppose q line
perpendicular to the directio of the furrow aud
equal to its breai;h,) the farrow slice is to be
lifted and turned over, revolving about its edge
knfo uAff fhn altnn
the dimensions of which are inches by 10, is ex-
hibited in the diagram.
Professor H. here illustrated on the black
AS this effect is to be produced by the mould
board in contact with the whole breadth of the fur
row slice, it is evident that the surface Of the
mould board must be warped surface, &c aerated
by right line moving from the position Of the
front edge ef the SHARE parallel to plane director
which isperpendcular to the direction Of the furrow
the generatrix at the time revolving about its
inner extremity describing an angle of l35 deg. or
leO deg, according to the position in which the
furrow slice is ts be left, this whole angle being de-
scribed when the generatrix has moved the pre-
scribed length of the plough; feet being the maxi
num-
The only resistance to the turning over of the
furrow slice, after it is cut off, will be its
OF nertial and weight. The friction occasioned by
the weight of the furrow slice will impede the fer
ward motion of the plough, but forms no part Of
the resistance of the furrow sli,e itself to being
turn ed over
But this friction is trihing, compared with tn 1T
of the bottom of the plough, (Which depends on its
weight. and not on the length of The plough or the
surface in contact with the ground,) and still more
triHipg in comparison with the resistance which the
sod earth opposes to the cutting Of the coulter and
the share
The problem will then consist sim ply in deter
mining the relation of the angular movement of the
generatrix to its longitudinal movement, SO as to
produce steady and constant pressure of the
mould board upon the furrow slice till it is COM
DletelV
These conditions will insure both the least resist
ance, SO far the small resistance, arising from the
weight and inertia of the furrow slice, concerned,
and the best performance of the work.
For the equation which expresses the relations
of angular motion and time, or in other words, The
Angular velocity of solid bodies about fixed axes
unoer the action Of various accelerating forces,
see Poisson, Irate de Mecanique, arr. 392, Of the
edit. of 1888
Professor II. then displayed upon the black
board an investigation involving the higher mathe-
ma,ieal analysis, fro N which he deduced the law
Of generation OF the surface of the mould board,
anc explained practical method of constructing
model from wood, in accordance with his formula,
30 as to fulfil the conditions prescribed.
For the purpose of producing the pulveriz alton Of
the furrow slice there must be an elevation of tho
mould board a, its under surfa &c medium line.
This elevation will act to the greatest advantage to
produce the pulverization, II made u oon the for
part Of the mould board, where the surface is
not SO much warped. Experiments might be made
with an excres, ,ence Of wood, which should be cut
away until the degree Of Pulverization leaves tae
furrow slice in sufficient form to be turned over
and delivered in its place without too great scat
tering.
VIEWS OF THE NATURE OF ORGANIC STRUCTURE,
BY LIEBT. c. b. HUAT, CORPS OF ENGINEERS,
Throughout the whole range of organic exist
epce, both animal and vegetable. there is evil
dent adaptation Of species and individuals to the
particular circumstances in which they found.
Nor is it less true that all animals aud vegetables
exhibit broad general adaptation to the great cos
Dical and chemical peculiarites Of the eartn itself
The conditions indispensable for the exis ;ence Of
each organi, species such that wecannot imagine
its vital possibility except in its present astronomi
cal habitat Any great change from the earth's
values for gravit ation-tae pheric pressure
the average heat and light, or greatly increased
variations in these elements Of condition would
prove fatal to all our present species. Nor could
these species long survive fundamental change
in the atmosphere-the water-the vapocs, or the
soils Of the pres, Mt terrestrial system
The problem of conditions OF existence. has an
astronomical or cosmical phase We can conceive
n planet with platinum, gold, and silica coat,-
nonts, with a mercurial atmosphere, with ele-
ments whose combinations should bo q hundred
fold more refractory than ours, and yet with teg-
persture conditions such that its aggregates Of
Inorganic matter should be much the ,ine as we
now see. Moreover, We can conceive the existence
there Of vital organic forms, composed Of elements
wholly different from those entering organic bodies
here, but whose functions should be performed ex-
actly 10 nifty with earthly analogies.
How vastly unlike in physical features are this
earth Neptune, and Mars. yet some kind OF mic
life Is, doubtless, actually existent on each. TIE
structure Of material FORMS ftted to perform or
ganic functions, involves idea Of the highest ge-
herality, and rs mechanically possible in ndaity
Of material conditions. Either the organic form
or the habitat being given or predetermined, an
intellect efficiently capacious could determine the
other by pue computation. II to this intellect be
supersddtd the power Of giving material form or
expt ssion to these computed results nothing more
would be necessary tor placing any conceivable
organic type in its proper home or In orning for any
home Its proper organic nhabitan. Man sintelleet
quite stfhces 10 CONCEIVE how the Divine ore ,tive
miHo migi infinitely vary organic forms in simple
adaptation 10 their dissinilar homes throughout
this VIDE universe. The historic order ia forming
for all these varieties, the terms of the existing
relation between home and inhabitant, has beeu,
see mngly, first TO arrange the home, and thea to
construct the inhabisnt The species actually
setn around Us, embody the Divine solutions Of
those particular problems furnished by their spe
ciac physical circumstances. The rsnge of varia