galtrop 
galtropt (gal'trop), n. Same as caltrop. 
Errours in Divinity and Policy . . . are the cursed Coun- 
ter-mures, dropt Portcullises, scouring Angiports, sulphu- 
riousGranado's, laden murtherers. peevish Gallhropex, and 
rascall desperadoes, which the Prince of lyes Imployes 
with all his skill and malice, to maintaine the walls and 
gates of his kingdome. N. Ward, Simple Cobler, p. 1\>. 
galuchat(F. pron. ga-lu-sha'), . [F.] A kind 
of shark's skin or shagreen usually dyed green, 
used to cover cages, boxes, etc. As prepared 
it retains the tubercles with which it is stud- 
ded in the natural state. 
galvanic (gal-van'ik), a. [= F. galvanique = 
Sp. galvdnico = Pg. It. galvanico (cf. D. G. gal- 
ranisch = Dan. Sw. galvanisk), < Galvani : see 
galvanism.'} 1. Pertaining to galvanism, or 
current electricity as produced by a chemical 
battery (see electricity) : same as voltaic, a word 
in more common use. 
All the galvaniek combinations, analogous to the new 
apparatus of Mr. Volta, . . . consist ... of series, con. 
taintng at least two metallic substances, or one metal and 
a stratum of fluids. 
Sir H. Dam/, Philos. Trans. (1801), ii., art. 20. 
2. Spasmodic, like the movements of a limb 
produced by a current of electricity : as, a gal- 
vanic start Galvanic battery, cautery, current, 
ecraseur, etc. See the nouns. Galvanic induction, 
induction of electric currents. 
galvanical (gal-van'i-kal), a. [< galvanic + 
-.] Same as galvanic" 
The phenomena of magnets, of electrical bodies, of oal- 
rn in fnl apparatus, seem to form obvious material for such 
sciences. Whewell, Philos. of the Mechanical Sciences. 
galvanisation, galvanise, etc. See galvanisa- 
tion, etc. 
galvanism (gal'va-nizm), n. [= D. G. gah-a- 
iiixiinin = Dan. gdh'anisme = Sw. galvanism = 
F. galvantsme = Sp. Pg. galvanismo, < It. gal- 
vanismo, so called after Luigi Galvani, professor 
of anatomy at Bologna (1737-98), the first in- 
vestigator in this field. His theory was first pub- 
lished in 1792.] 1. That branch of the science 
of electricity which treats of electric currents 
more especially as arising from chemical action, 
as from the combination of metals with acids. 
The name was given before the identity of this form of 
electricity and that produced by friction was fully under- 
stood : It is now nearly obsolete. See electricity. 
2. In med., the application of an electric cur- 
rent from a number of cells: in distinction 
fromfaradism or the use of a series of brief al- 
ternating currents from an induction-coil, and 
from franklinism or the charging from a fric- 
tional or Holtz machine. 
galvanist (gal'va-nist), n. [As galvan-ism + 
-is*.] One versed in galvanism. 
galvanization (gal'va-ni-za'shon), n. [< gal- 
vanize + -ation.] The act of galvanizing, or 
the state of being so affected. Also spelled gal- 
vanisation. 
galvanize (gal'va-niz), . t. ; pret. and. pp. gal- 
vanized, ppr. galvanizing. [= D. galvaniseren 
= G. galvanisiren = Dan. galvanisere = Sw. 
galvanisera = F. galvaniser = Sp. galvanizar = 
Pg. galvanisar = It. galvanizzare ; as galvan- 
ic + -ize.] 1. To subject to the action of an 
electric or galvanic current, as in medicine. 
The word is especially used of the act of restoring to con- 
sciousness by electrical action, as from a state of suspend* 
ed animation; or of electrical restoration to a semblance 
of life, as a corpse or a severed part of the body. 
The agitations resembled the grinniugs and writhing* 
of a galvanised corpse, not the struggles of an athletic 
man. Macatday, On History. 
Hence 2. To confer a fictitious vitality upon ; 
give a mechanical semblance of life or vitality 
to. 3. To plate, as with gold, silver, or other 
metal, by means of galvanic electricity; elec- 
troplate. 
Also spelled galvanise. 
Galvanized Iron, a name given (a) improperly to sheets 
of iron coated with zinc by a non-galvanic process, the 
iron being first cleansed by friction and the action of dilute 
sulphuric acid, and then plunged into a bath composed of 
melted zinc and other substances, as sal ammoniac, or mer- 
cury and potassium ; (6) properly, to sheets of iron coated 
first with tin by a galvanic process, and then with zinc by 
immersion in a bath containing fluid zinc covered with sal 
ammoniac mixed with earthy matter. 
galvanizer (gal' va-m-zer), n. One who or that 
which galvanizes.' Also spelled galvaniser. 
galvano-. Combining form of galvanic or gal- 
vanism. 
galvanocaustic (gaFva-no-k&s'tik), a. [< gal- 
vanic + caustic, q. v.]" Relating to the heat 
derived from a current of electricity when em- 
ployed in cauterization. 
galvanocauterizatiqn (gal*va-no-kate-ri-za'- 
shon), n. [< galvanic + cauterization.'] Cau- 
terization by the heat induced by a current of 
electricity. 
2444 
galvanoscope 
galvanOCautery ( gal'va-no-ka'te-ri ), n. ; pi. rent, and, as the opposing action of the earth is greatly 
galvanocauteries (-riz). i'< nalrame + canton/.! e "' eeb l e 'l ty the combination, a much larger deflection is 
In surg., a cautery in which a galvanic current "** would be given by one of the needles if em- 
is used to heat the cauterizing part of the ap- 
paratus. 
galvanoglypb. (gal'va-no-glif), n. [< galvanic 
+ Gr. yAtfttv, engrave.] A picture produced 
by galvanoglyphy. 
galvanoglypny (gal-va-nog'li-fi), n. [As gal- 
i-iiiKiijIif/ili + -i/."\ A method of producing an 
electroplate which may be used m a printing- ter, a galvanometer in which rhL~need"ie"i?so "dimmed, 
press. The essential features of the process are the use by induction or otherwise, that on the passage of a cur- 
of a zinc plate covered with a ground, and etched as a " 
matrix for an electroplate, the reverse plate thus obtained 
being used in printing. The picture obtained by this 
method is called a ffalvanoglyph. 
galvanograpb. (gal'va-no-graf), n. [< gulrun- 
ic + Gr. ypo^wv, write.] 1. A plate formed by 
the galvanographic process. 2. An impres- 
sion taken from such a plate. 
ployed alone. Galvanometers are also made astatic by 
the use of a fixed magnet so placed as to counteract the 
influence of the earth's magnetism. Ballistic galva- 
nometer, an instrument used to measure the strength 
"l a current which acts for only :i very short time, as that 
produced by the discharge of a condenser. It involves 
the use of a heavy needle, which takes a relatively long 
time to swing. The sine of half the angle of the flrst 
swing is proportional to the quantity of electricity which 
lias Mowed through the coil. Dead-beat galvanome- 
. - . . to galvauog- 
raphy. 
galvanography (gal-va-nog'ra-fi), n. [As gal- 
vanograph + -y.] A 'process for producing 
plates which will give impressions after the 
manner of a plate used in copperplate engrav- 
ing. The drawing is made on a silvered plate in viscid 
paints, in such a way as to leave the dark parts slightly 
raised. An electrotype is taken from this, which may be 
used as an engraved plate, the dark lines now being de- 
pressed precisely as in a copperplate. An impression from 
such a plate is called a galvanograph. 
galvanologist (gal-va-nol'o-jist), . [< galra- 
nology + -ist.~\ One who describes the phenom- 
ena of galvanism. 
galvanology (gal-va-nol'o-ji), w. [< galvanic 
+ Gr. -Aoj-io, < teyciv, speak: see -ology.~\ A 
description of the phenomena of galvanism. 
galvanomagnetic (gal'va-no-mag-net'ik), a. 
Same as electromagnetic. 
galvanometer (gai-va-nom'e-ter), n. [(.galvan- 
ic + Gr. fierpov, a measure.] An instrument 
for detecting the existence and determining the 
strength and direction of an electric current. 
In all galvanometers the principle of action is the same. 
It depends upon the force which Oersted discovered to 
be exerted between a magnetic needle and a wire carry, 
ing a current a force which tends to set the needle at 
right angles to the direction of the current, and whose 
Intensity, other things remaining the same, depends di- 
rectly upon the strength of the current 
The term galvanometer is applied to an instrument for 
measuring the strength of electric currents by means of 
the deflection of a magnetic needle round which the cur- 
rent is caused to flow through a coil of wire. 
S. P. Thompson, Elect and Mag. 
Aperiodic galvanometer, a dead-beat or thoroughly 
damped galvanometer. Astatic galvanometer, an in- 
strument which consists of a pair of similar needles mag- 
netized, with their poles turned opposite ways, and stiffly 
connected at their centers, sothat both ill awing together. 
Astatic Galvanometer. 
The one tends always to turn in a direction opposite to the 
other under the earth's magnetic attraction, so that if the 
needles were perfectly alike they would form a perfectly 
astatic pair, or a pair that would not tend to assume any 
particular direction from the magnetic influence of the 
earth. One of the needles, nb, is nearly in the center of 
the coil, CDEF, through 
which the currentpasses; 
the other, a'b', just above 
the coil. When a current 
traverses the coil in the 
direction of the arrows, 
the action of all parts of 
the current upon the low- 
er needle tends to urge 
the austral pole a toward 
the back of the figure and 
the boreal pole 6 to the 
front, while the upper 
needle, a'b', is affected principally by the current CD of 
the coil, which urges the austral pole a' to the front of the 
figure and the boreal pole // to the hack. Both needles 
are thus urged to rotate in the same direction by the cur 
rent it will move to its final deflection without oscilla- 
tion. Differential galvanometer, a form of galva- 
nometer in which the coil consists of two separate wires 
wound side by side, and used to compare two currents. 
If the currents are sent in opposite directions through 
these wires the motion of the needle will be determined 
by the difference in their intensity ; if they were equal the 
needle would remain stationary- Sine galvanometer, 
a magnetic needle poised at the center of a coil of insu- 
lated copper wire wound round a vertical circle that may 
be turned horizontally on its stand. In use the needle and 
vertical circle are at flrst both in the magnetic meridian. 
When a current passes, the needle is deflected, and the 
vertical coil is turned by the observer until its plane coin- 
cides with the magnetic axis of the needle. The strength 
of the current is as the sine of the angular deviation. 
Any sensitive galvanometer in which the needle is di- 
rected by the earth's magnetism can be used as a sine 
imlmjurmeter, provided the frame on which the coils are 
wound is capable of being turned round a central axis. 
S. P. Thompson, Elect, and Mag., p. 167. 
Tangent galvanometer, a very short magnetic needle 
delicately suspended so as to tuni in a horizontal plane. 
The point about which it turns is at the center of a ver- 
tical coil of copper wire through which the current is 
passed. The diameter of the coil is at least ten or twelve 
times the length of the needle. The needle is therefore 
usually not more than half an inch long ; and, for conve- 
nience of reading its deflections, long light pointers of 
aluminium or of glass fiber are cemented to its ends. In 
use the instrument is placed so that the vertical coil of 
copper wire is in the plane of the magnetic meridian. The 
current is then sent through the coil, and the angle by 
which the needle is deflected is read on*. The strength of 
the current then is proportional to the tangent of the an. 
gle of deflection, whence the name of the instrument- 
Thomson's mirror galvanometer, the most sensitive 
galvanometer yet invented. Its needle, which is very 
short, is rigidly attached to a small, light, concave mirror, 
and suspended in the center of a vertical coil of very small 
diameter by a silk fiber. A movable magnet is provided 
for bringing the needle into the plane of the coil when 
the latter does not coincide with the magnetic meridian, 
and also for rendering the needle more or less astatic. 
Needle, mirror, and magnet weigh only about Ij grains. 
At a distance of two or three feet from the mirror is a solid 
wooden stand, with a graduated scale, facing the mirror. 
In the stand, just under the center of the scale, a hole is 
cut, and a fine wire is stretched upright across it. A strong 
lamp stands behind the opening, so that its light will fall 
on the mirror and be reflected back on the scale. An 
image of the wire will thus be constantly thrown on the 
scale, and the slightest motion of the needle and its mir- 
ror will produce a much greater motion of this image. 
As the current flows the one way or the other the index 
will move to one side or the other. This galvanometer 
was devised for use in connection with the Atlantic sub- 
marine cables. It was long the only instrument with 
which signals could )>e read through long submarine lines ; 
and it is still employed to a great extent, though now super- 
seded by the siphon-recorder of the same inventor. 
galvanometric (gal"va-no-met'rik), a. [As gal- 
vanometer + -ic.] Pertaining to the galva- 
nometer or to galvanometry: as, the galvano- 
metric needle. 
galvanometrical (gal"va-no-met'ri-kal), a. 
Same as galvanometric. 
The parts of the stand include . . . the necessary clamp- 
Ing screws for electrical and galvanometrical connections. 
The Engineer, LXV. 510. 
galvanometry (gal-va-nom'e-tri), n. [As gal- 
vanometer + -y.~] Th'b art or process of deter- 
mining the strength of electric or galvanic cur- 
rents; rheometry. 
galvanoplastic(gal*va-no-plas'tik),rt. [Asgal- 
ranoplasty + -ic.] Pertaining to the reproduc- 
tion of forms by electrotypy Galvanoplastlc 
process, a method of obtaining copies of type, an engrav- 
ing, a design, etc., by electrical deposition : ordinarily the 
same as electrotyping. As applied to art-work, the phrase 
refers to the process of electroplating a plaster model with 
bronze, the mold being afterward destroyed and the plas- 
ter withdrawn, leaving a hollow figure in bronze. As ap- 
plied to ornamental work in glass, the phrase is used for 
a method of decorating glass surfaces by means of electro- 
plating, the design being flrst traced on the glass in some 
metallic pigment and burned in. 
galvanoplasty (gal"va-no-plas'ti), n. [_=F.gal- 
vanoplastie; as galvanic + Gr. 7r/.aorof, < ir/,aa- 
ceiv, form.] Same as electrotypy. 
fl galvanopuncture (gaFva-no-pungk'tur), TO. [= 
F. yalvano-puncture ; as galvan-ic + puncture.] 
In med., the passage of a constant current 
through a part of the body by means of needle- 
shaped electrodes introduced into it. 
galvanoscope (gal-van'o-skop), n. [=.F. gal- 
vanoscope; as galvanic + Gr. cuovtiv, view.] 
direction of an electric current. A magnetic 
needle may be used as a galvanoscope. 
