404 HUSBANDRY. 
bles, will be found to anfwer well for a gate that is in¬ 
tended to open only one way. Suppofing the face of the 
hanging-poll to be let perpendicular, and tl^e upper hook 
driven in near its inner angle, and that the lower hook 
mull be four feet and a halt below it ; fufpend a plumb- 
line from the upper hook, and at four feet and a half 
mark the poft; then, at one inch and a half farther from the 
gateway than this mark, drive in the lower hook ; this 
hook mull projeft about half an inch farther from the 
face of the poll than the upper hook. A gate thus hung 
will, when thrown open nearly to the line of its highelt 
elevation, return to the falling-poll with a velocity fufii- 
cient to refill a moderately-llrong wind. This velocity 
will be either increafed or diminilhed, accordingly as the 
upper hook declines more or lei's from a pofition perpen¬ 
dicular to the lower hook. .In order to adapt the thim¬ 
bles to thefe hooks, as the lower hook is one inch and a 
half farther from the gateway than the upper hook, the 
lower thimble mull have its eye an inch and a half farther. 
from the heel of the gate than the eye of the upper thim¬ 
ble, in order that the bars of'the gate may be in a hori¬ 
zontal pofition when it is Ihut. And, as the upper hook 
projects half an inch lei's‘from the hanging-poll than the 
lower hook, the upper thimble lhould be fixed half an 
inch nearer the, farther fide of the heel of the gate than 
the lower thimble, in order that the gate may be in a 
perpendicular pofitidn when Ihut. If the thimbles have 
ilraps embracing the heel of the gate, and proceeding a 
few inches alongeach fide of the bottom and top bars, and 
if they are fixed to the heel bars and braces, by means of 
iron pins, and ferew-nuts, great firmnefs will be given to 
the gate at thole two points, which are thole that iuffer 
the greatell {trains.—For this improved gate Mr. Waittell 
received the public thanks of the Society for the Encou¬ 
ragement of Arts and Manufactures^ 
But the mofl fcientific mode of hanging and Tecuring 
a very ftrong and ufeful gate, is prefented to us by 
Thomas N. Parker, efq. A plan of this gate is delineated 
in the Engraving.at fig. 4- in which the top rail is fup- 
ported by^a long-diagonal lacing let into the' heel of the 
gate with a ftrong biitment, and fecured from warping by 
the two upright lacings ; the upper thimble being attach-^ 
ed to, or ‘forming a part of, a long bar or ftrap of iron of 
the fame length as the gate., is fattened at the one end by 
a flout (houldering, ami at the other by a ferew-nut, and 
the. whole is put together with icrews: by this plan the 
gate is riot likely to fink at the head, neither is the top 
rail weakened with mortifes, but greatly llrengthened by 
the iron flrap. 
Mr. Parker then proceeds to the nicety of hanging his 
gates: On the principles here laid down, fays Mr. Par¬ 
ker, a gate is confidered as a lever of the fecond kind; 
and, when fufpended by hooks or pivots precifely perpen¬ 
dicular to each other, it vvill.be at reft wherever it may 
be placed ; but, by the fmalleft variation of the hooks 
from their perpendicular pofition (provided it be fuffi- 
cient to overcome the fnCliou), a gate will acquire one de¬ 
terminate line of reft, and an oppofition-line of equili¬ 
brium ; and confequently, from any part of a circle which 
a gate fo fufpended may be made to deferibe, it mull have 
a cohftant tendency to fall to that line of reft. 
When a gate is in its line of reft, or oppofite line of 
.equilibrium, the hooks and the centre of the gate’s gra¬ 
vitation will be in one and the fame vertical plane ; and, 
when the hooks are perpendicular to each other, it can 
admit of no doubt that they muft be in the fame vertical 
plane with the centre of the gate’s gravitation, becaufe 
they will be fo with any third given point whatsoever. 
The requisite velocity for the fall of a gate which opens 
but one way, is obtained by an extra length of the lower 
thimble, or, more properly, by the horizontal diflance of 
two perpendicular lines, one falling from the centre of 
each of the hooks or pivots upon which a gate is fui'pend- 
eft; and the proportion is not to be determined fo much 
by the length and weight of the ggte, as from the diflance 
of two hinges from each other; about a quarter of an 
inch muft alfo be added to the extra length of the lower 
thimble for what is loft in the hanging of the gate, exclu- 
five of the perpendicular difference of the two pivots. 
The velocity given to the gate^ fall by the extra length 
of the lower thimble, is calculated for fuch hinges as are 
rounded off and well-finilhed; it being now ascertained. 
“ that the fmalleft furface will have the leall friflion.” 
See Mr. Vince’s Experiments “ On the Motion of Bodies 
a lie tiled by Friftion,” Phil. Tranf. vol. Ixxv. 
A gate nine feet long fliould rife at the head in open¬ 
ing about fix inches, by which it will acquire a lufficient- 
tendency to fall to its line of reft; and, fuppoling the 
hinges to be forty inches afunder, it follows, that as the 
length of the gate is to the difference between the height 
of the head of the gate when in its natural line of reft, 
and the height of the head of the gate at its-greatefl ele¬ 
vation, or oppofite line of equilibrium, fo will be the dif- 
tance of the two hooks to double the clear extra length 
of the lower thimble; that is, reducing it to inches, as 
108 : 6 : : 40 : 2 -^ : therefore, this extra length of the 
lower thimble fliould be igg-, including the rfe allowed 
for what is loft in the hanging. From this proportion 
may be deduced any other ; for example : if the diflance 
of the two hinges were 30 inches, then the extra length 
of the lower thimble would be i^Wj hecaule as 40 : 
:; 3° : ^f, and if + t 3 2 1 fuppofing a gate to be a 
right-angled parallelogram, or equivalent thereto as far as 
regards its upright fulpenfiori. See fig. 5. 
A gate, being thus hung, will not fall with an uniform¬ 
ly-accelerated motion, as might be imagined, but with a 
velocity fomewhat increafed towards the middle part of 
its femi-circular coufife, and retarded again in approach¬ 
ing its line of reft, coinciding with a proportionate rife of 
the head of the gate; one-half of which rife, or three inches, 
it attained in the firft half, orgo 0 , of the gate’s femi-circu¬ 
lar motion from its line of reft, and the other half or three 
inches is added in completing the lupplementary arc of 
90 0 , but fubjefl to certain variations in the intermediate 
parts of the gate’s motion, viz. as the verfed fine of the 
angle formed by the gate with its line of reft is to the 
length of the gate which is made radius, fo will be the cor- 
refponding rife of the head of the gate to three inches, at 
any given angle within the quadrant : and the rife of the 
head of the gate afterwards will be, as the co-Jine of any 
given angle formed by the’gate with its line of equili¬ 
brium, is to the length of the gate or radius, fo will be 
the correfponding rile of the head of the gate to the re¬ 
maining three inches. And by calculation it appears, that 
the -rife of the head of the gate will be as follows in each 
22 0 '30' or -|th part of its femi-circular motion from the 
line of reft to the line of equilibrium : 
1 the ill 
it will rife 
5^- of an ii 
2d 
ditto 
ditto 
7 
3d 
ditto 
ditto 
I 
4th 
ditto • 
ditto 
1-2- 
1 1 2 
5 th 
ditto 
ditto 
1-2- 
1 1 2 
6th 
ditto 
ditto 
I 
7 th 
ditto 
ditto 
7 
8 th 
ditto 
ditto 
-12 
Total 
180 0 w: 
ill give the rife 
of 6 inches. 
Fig. 6,reprelents the horizontal feclionof two gate-polls, 
with black fpots where the hooks.ought to be placed, the 
fal ling-poll meeting the gate at ^tli of the lemi-circle or 22 0 
'30: Ihort of its line of relt, the better to refill the effects of 
wind ; the upper thimble being placed about half an inch 
nearer to the hanging-poft, and the upper hook propor- 
tionably lliorter than the lower one, the gate.will be upright 
when fattened, notwithftanding it be fo much .Ihort of its 
line of relt. Half an iijch may be afeertained to be the pro¬ 
per allowance for the above purpofe, thus : take a com¬ 
mon horizontal diltance of two perpendicular lines, one 
falling from each of-the hooks 1 y^tns inch,, to which I 
have an angle of 22 0 30' given, and a right angle parallel 
1 - to 
