THE CULTIVATOR. 
203 
■what all admit and are friendly to, so few will take the trouble to pro¬ 
mote. This great interest that clothes, feeds, supports and educates all— 
that matures every other, is apt to be made too subservient to the trifling 
pursuits of the moment—and while all little meetings,-involving no volua- 
ble or permanent interests, will be well attended, one to promote agricul¬ 
tural improvement is commonly overlooked or neglected. 
Some think it is quite enough to promote the interest of agriculture, if 
they give a dollar or two to the funds of a society: but, gentlemen, your 
money is of little consequence compared to your presence at such con¬ 
ventions. It is the encouragement of your personal attention; it is the in¬ 
terest you take in discussing subjects of improvement; it is the light that 
is elicited by a comparison of ideas, of those who have practiced what they 
have read and thought on. It is these that give interest to the subject, 
and push it on its march to improvement, much more than any pittance 
in money. At the last meeting of the convention, committees were ap- 
appointed to report upon several interesting subjects, to the subsequent one 
in .February next. As these subjects bear materially upon the improve¬ 
ment in the different branches of agriculture, and as they have been most¬ 
ly committed to gentlemen who are willing and competent to discharge 
the duties assigned them, it is presumed that these reports will give much 
additional interest to the meeting, and that they will embrace a body of 
facts that will be peculiarly beneficial to the farmer. Is it not important 
for us to inquire what has been done the last year? What we have added 
to our stock of knowledge, or the comforts of our families? What have we 
contributed to the general welfare, and to advance the interest of our com¬ 
mon pursuit? We must not stand still, or continue to farm as our fathers, 
respectable as they were, have done: because we have long seen, that 
they pursued an extremely exhausting system. It is for us to keep pace 
with the advance of the age, and throw; not only the energies of our bo¬ 
dies, but of the mind, into the work. This we cannot do unless we meet 
and compare ideas, discuss new topics, hear all that can be said on the 
prosecution of the different branches of agriculture, and when we returu 
to our homes, apply these new thoughts, so gained, to the advancement 
of our daily pursuit. 
A thousand arguments, gentlemen, might be adduced, to show, noton- 
the need agriculture has of improvement, and the good results that will 
follow from our meeting—but let us ask, are they required? Is it even 
necessary to enumerate what is so obvious to all? Have we.then no am¬ 
bition to excel as farmers? No desire to promote our own or add to the 
prosperity of those around us? No “ esprit du corps ” attaches to all who 
are fond of their respective employments? It cannot be. We feel the 
assurance that as the former convention unanimously resolved to stand ad¬ 
journed to the first Thursday of February, 1S33, the meeting at that time 
will draw together a large number of the intelligent friends of agriculture. 
JOHN P. BEEKMAN, A. MTNTYRE, 
ANTHONY VAN BERGNN, JAMES McNAUGHTON, 
JESSE BUEL, J- K. PAIGE, 
TEUNIS VAN VECHTEN, LEWIS F. ALLEN, 
JOHN TOWNSEND, A. WALSH. 
December 28, 1838. 
Yornig Men’s Department. 
NATURAL PHILOSOPHY. 
II. Hydrostatics treats of the pressure and equilibrium of fluids. 
From the experiments which have been made in this branch in philoso¬ 
phy, the following important principles, among many others, have been 
deduced: . 
(1.) That the surface of all waters which have a communication while 
they are at rest, will be perfectly level.— This principle will be more 
clearly understood by an inspection of the following figures. If water be 
poured into the tube A, (fig- 52.) it will (Fig- 52.) 
run through the horizontal tube E, and rise 
in the opposite tube B, to the same height 
at which it stands at A. It is on this prin¬ 
ciple that water is now conveyed under 
ground, through conduit pipes, and made 
to rise to the level of the fountain whence 
it is drawn. The city of Edinburgh, a 
considerable part of which is elevated 
above the level of the surrounding coun¬ 
try, is supplied with water from a reser¬ 
voir on the Pentland hills, several miles 
distant. The water is conveyed in leaden 
pipes down the declivity of the hill,, along 
the interjacent' plain, and up to the en¬ 
trance of the castle, whence it is distribut¬ 
ed to all parts of the city. If the point A represent the level of the reser¬ 
voir, C D will represent the plain along which the water is conveyed, and 
B the elevation to which it rises on the Castle hill. On the same princi¬ 
ple, and in a similar manner, the-city of London is supplied with water, 
from the water-works at London Bridge. Had the ancients been acquaint¬ 
ed with this simple but important principle, it would have saved them the 
labor and expense of rearing those stupendous works ol art, the Aqueducts, 
which consisted of numerous arches of a vast size, and sometimes piled 
one above another. , , .. 
Fig. 53 represents the syphon, the action of which depends upon the 
pressure of the atmosphere. If this instrument be filled (Fig. 53.) 
with water, or any other liquid, and the shorter leg G, 
plunged to the bottom of a cask, or other vessel, contain¬ 
ing the same liquid, the water will run out at the longer 
leg F, till the vessel be emptied, in consequence ot the 
atmospheric pressure upon the surface of the liquid. On 
this principle, water may be conveyed over rising ground 
to any distance, provided the perpendicular height of the 
syphon ahoye the surface of the water in the lountain, 
does not exceed thirty-two or thirty-three feet. On the 
same principle are constructed the fountain at command, 
the cup of Tantalus, and other entertaining devices. The 
same principle, too, enables us to account for springs 
which are sometimes found on the tops of mountains, 
and for the phenomena of intermitting springs, or those 
which flow and stop by regular alternations. 
(2.) Any quantity of fluid, however small, may be 
made to counterpoise any quantity, however large .— 
This is what has been generally termed a Hydrostatical 
Paradox; and from this principle it follows, that a given 
quantity of water may exert a force several hundred times V'v J j 
greater or less, according to the manner in which it is - 
employed. This force depends on the height of the co¬ 
lumn of water, independent of its quantity; for its pressure depends on 
its perpendicular height. By means of water conveyed through a very 
small perpendicular tube, of great length, a very strong hogshead has 
been burst to pieces, and the water scattered about with incredible force. 
On this principle the hydrostatic press, and other y engines of immense 
power have been constructed. 
(3.) Every body which is heavier than water, or which sinks in it, 
displaces so much of the water as is equal to the bulk of the body im¬ 
mersed in the water. —On this principle, the specific gravities, or com¬ 
parative weight, of all bodies are determined. It appears to have been 
first ascertained by Archimedes, and, by means of it, he determined that 
the golden crown of the King of Syracuse had been adulterated by the 
workmen. From this principle we learn, among many other things, the 
specific gravity of the human body; and that four pounds of cork will per- 
serve a person weighing 135 pounds from sinking, so that he may remain 
with his head completely above water. 
Hydraulics, which has sometimes been treated as a distinct department 
of mechanical philosophy, may be considered as a branch of hydrostatics. 
It teaches us what relates to the motion of fluids, and how to estimate 
their velocity and force. On the principle of this science, all machines 
worked by water are constructed—as steam engines, water mills, com¬ 
mon and forcing pumps, s>phons, fountains and fire engines. 
III. Pneumatics.— This branch of philosophy treats of the nature and 
properties of the atmosphere, and of their effects on solids and fluid bo¬ 
dies. From this science we learn, that air has weight, and presses on all 
sides, like other fluids; that the pressure of the atmosphere upon the top 
of a mountain, is less than on the plain beneath; that it presses upon em¬ 
bodies with a weight of several thousands more at one time than at ano¬ 
ther; that air can be compressed into forty thousand times less space than 
it naturally occupies; that it is of an elastic or expansive nature, and that 
the force of its spring is equal to its weight; that its elasticity is increased 
by heat; that it is necessary for the production of sound, the support of 
flame and animal life, and the germination and growth of all kind of vege¬ 
tables. 
These positions are proved and illustrated by such experiments as the 
following:—The general pressure of the atmosphere is proved by such ex¬ 
periments as those detailed in No. 2 of the Appendix. The following ex¬ 
periment proves that air is compressible. If a glass tube, open at one 
end, and closed at the other, be plunged with the open end downwards, 
into a tumbler of water, the water will rise a little way in the tube; which 
shows, that the air which filled the tube is compressed by the water into ' 
a smaller space. The elasticity of air is proved by tying up a bladder, 
with a very small quantity of air in it, and putting it under the receiver of 
an air pump, when it will be seen gradually to inflate, till it becomes of 
its full size. A similar effect would take place, by carrying the bladder 
to the higher regions of the atmosphere. Gn the compression and elas¬ 
ticity of the air, depends the construction of that dangerous instrument, 
the air-gun. 
That it is capable being rarified by heat, is proved by holding to the fire 
a half blown bladder, tightly tied at the neck, when it will dilate to neatly 
its full size; and if either a full blown bladder, ora thin glass bubble filled 
with air is held to a strong fire, it will burst. The elasticity of the air is 
such, that Mr. Boyle, by means of an air-pump, caused it to dilate till it 
occupied fourteen thousand times the space that it usually does.—That air 
is necessary to sound, flame, anim&l.and vegetable life, is proved by the 
