Part 14
“It often happens, that some of the limbs of fruit trees, trained against a wall, are blighted and die; while others remain in a healthy and flourishing state. This evil is, by gardeners, generally attributed to the effects of lightning. But, if this were the case, would not the violent action of the electric fluid produce a laceration of the branch and stalk of the tree? No such effect is to be perceived. It therefore appears to me, that we must seek some other cause for this evil, and I flatter myself that I have discovered the real one.
A few years since, when Galvanism was first introduced to public notice, I constructed a pile, consisting of about one hundred plates of copper and as many of zinc, each about two inches square. Among other experiments, I applied it to the branch of a tender plant, (a species of the ficoides.) Having left it for about an hour, on my return I found the branch withered, and hanging close to the stalk. It immediately occurred to me, that Galvanism might be the cause of the above mentioned defect in wall fruit trees, occasioned by the oxydation of the nails, by which they are oftentimes fastened (for I conceive Galvanism to be produced, in a greater or less degree, by every metal passing into a state of oxydation.) Recollecting that the limb of a cherry tree in my garden had, nearly a year before, been fastened to the wall with an iron cramp, I instantly examined it, and found it dead; though, when fastened, it was a flourishing, healthy limb, at least an inch in diameter, and nine feet in length.
I have since examined several peach and nectarine trees; and wherever I discovered a limb dead, I invariably found that one or more of the nails which fastened it were in _contact with the bark_. A limb of a peach tree puzzled me for some time. It was dead, but I could not perceive that any of the nails were in contact with it, (the scraps of cloth being left pretty long.) After a narrow search, however, I found the mud, of which the wall was built, considerably stained with rust, immediately under the branch: and on digging into the wall with my knife, I brought the hidden mischief to light.—It was part of a very large spike nail, and which lay about an inch below the surface.
On mentioning some of those circumstances to a friend, he observed, that about a year before, he had fastened some currant trees to a wall, with iron hooks. On examination, almost every limb so fastened, _was dead_.
The effect of the Galvanism in these cases will probably be found to be greater in rainy seasons, as the oxydation then goes on more rapidly than it does at other times.
Hence it appears that, in training fruit trees, wooden pegs or cramps, should be used instead of iron; or else, that care should be taken that the iron do not touch or come near to a limb.
CHAP. XI. _Of medical Galvanism._
Galvanism, like electricity, has been applied to the human body, for the purpose of removing complaints, and apparently with equal success.
The ingenious Galvani, immediately after his discovery of Galvanism, (or as he called it, _animal electricity_,) attempted to explain the causes of several diseases by it. Thus in a complaint where there was a total loss of contractile power, as the paralysis, he ascribed the cause to the interposition of a non-conducting substance, which prevented the passage of the Galvanic fluid from the nerve to the muscle, and from the muscle to the nerve. “If artificial electricity (says he,) be conveyed to the head, the nerves or spinal marrow, by means of the conductor of the Leyden phial, paralysis, apoplexy, and even death, will be induced, according as the phial is charged with a greater or less quantity of the electric fluid.—If such effects result from _common_ electricity, may it not be presumed that a sudden afflux of _animal_ electricity towards the brain, may be productive of the most fatal consequences.”
But omitting, as wholly conjectural and unsatisfactory, all _theories_ relating to the effect which Galvanism has upon the animal œconomy, we shall proceed to relate known facts, and the method of applying Galvanism for the relief of certain morbid affections of the human body.
The general mode of operating with Galvanism, is to apply small portions of it at first, and gradually to increase the shock, as circumstances may dictate. It has been customary to remove the cuticle (by means of a blister or otherwise,) from the parts of the body to which the wires, communicating with the two extremities of the battery, are to be applied. This method, which was adopted because the cuticle is a very bad conductor, gave excruciating pain to the patient. Mr. Wilkinson has found it unnecessary, as by moistening the parts, and applying pieces of gold leaf or Dutch-metal, he has succeeded in producing the desired effect. During an operation, one of the conducting wires should be kept in contact with one of the metallic leaves, while the other conductor is to be removed, immediately after it has been brought in contact with the other metallic-leaf—and then replaced and removed successively.
The negative wire of a battery is the most powerful, and it is necessary in some cases to attend to this fact.
In a short time after Galvanism has been applied to a part of the body, a redness becomes perceptible about the part; and if the application be continued too long, vesications and ulcerations will be produced. These symptoms are a little troublesome at first, but do not require any particular treatment for their cure.
Galvanism should be applied twice in twenty four hours, otherwise it is supposed the intervals would be so long, as to prevent any good effects which might arise from it.
We shall now enumerate some disorders in which Galvanism has proved beneficial. In _paralytic affections_ it has afforded considerable relief.—Two instances of _mental derangement_ are recorded by professor Aldini, nephew to Galvani, in which its effects were truly surprising.—One of them afforded an instance of a gradual diminution of the mental energies, which ultimately sunk into stupidity. The other was of an opposite nature:—the system was in a state of violent excitement, and the patient raving and unmanageable.
In _rheumatism_, _spasmodic affections_, and _deafness_, where it does not arise from a natural defect in the organ, Galvanism has been applied generally with advantage. But the most astonishing effects of this wonderful principle have been displayed in cases of _suspended animation_. Mr. Humboldt made the first experiments relative to this part of our subject, on apparently dead linnets. He put a piece of zinc into the bill, and thrust a sharp piece of silver into the bird, near the other extremity of the body—he then formed a communication between the two, by an iron wire. “What (exclaims he) was my surprise, when I perceived, the moment the contact took place, the linnet open its eyes, stand erect on its feet, and flutter its wings; it again breathed during six or eight minutes, and then expired tranquilly.”
Galvanism is now applied to persons apparently dead, from drowning, hanging, or exposure to noxious gases. In such cases, the body should be divested of its clothing, and placed in a warm bed nearly approaching the natural temperature, and at the same time slight Galvanic shocks should be passed through the body, in such a direction as to affect the heart.—Thus by combining this, with the usual means, the most advantageous consequences may be expected. It may be laid down as a principle, that, in all cases where animation is suspended, and the principle of irritability not destroyed, the stimulus of Galvanism and electricity, if prudently employed, may rouse the dormant energies of vitality, and restore the system to its natural state of activity.
CHAP. XII. _The Identity of Galvanism with Electricity considered._
It has been supposed by many, that the phenomena of Galvanism and electricity depend upon the _same_ cause. Others, however, controvert this opinion, and affirm that Galvanism is a fluid _sui generis_. That there is a great similarity between some of the phenomena of Galvanism and those of the electric fluid, is evident; but this analogy cannot be traced in every instance.
It is not our province to enter into this controversy; we shall only relate a few facts upon which it is founded, and leave the speculative reader to draw from them his own conclusions.
_Facts which seem to indicate that Galvanism and Electricity are the same Fluid._
Both Galvanism and electricity exhibit light, in their passage from one conductor to another, through an intervening space of air.
Both affect an electrometer.
The deflagration of metals may be produced by either.
Electricity, as well as Galvanism, produces muscular contractions in animals, a short time after death.
_Facts in which Galvanism and Electricity differ from each other._
Some _good_ conductors of electricity are not good conductors of Galvanism; as was shewn by Dr. Fowler.
The manner of exciting Galvanism is different from that of exciting electricity;—the former being collected most copiously from _conductors_, and the latter from _non-conductors_.
The electric fluid affects the sense of smelling—but no smell has ever been observed from Galvanism.
The electric shock operates on the body by a sudden and percussive effect—while the one which follows the Galvanic process seems to arise from a constant current, attended by a jarring and tremulous sensation.
In the decomposition of water by Galvanism, hydrogen gas is formed at one of the wires, and oxygen at the other. In that by electricity, both gases arise from the same wire.
FINIS.
INDEX TO THE EPITOME OF ELECTRICITY.
A
_Æpinus’s_ theory of electricity, 115
_Amalgam_, directions for making the best kind of, 126
_Apparatus_, electrical, directions for using the, 68
_Attraction_, electrical, 21
_Aurora Borealis_, how to imitate the, 79
B
_Balloons_, inflammable air, 77
_Battery_ electrical, and experiments with it, 28
_Bells_, electrified, 76
_Black lead_, useful for points to lightning rods, 51
_Bladder_, electrified, 93
_Bolognian stone_, artificial, to make, 127
_Bottle director_ described, 65
C
_Candle_, to light a, 91
_Cannon_, the electrical, 96
_Cards_ pierced by electricity, 90
_Cavallo_, general laws deduced by him from experiments made with electrical kites, 46
_Cement_, how to make, 125
_Charcoal_ useful at the lower extremity of lightning rods, 53
_Chemical_ theory of electricity, 111
_Clay_ swollen by the electrical shock, 90
_Colours_ changed by the electrical shock, 87
—— experiments on, 87, 88
_Communication_, electrifying by, 15
_Conductors_, of, 6
—— luminous, 82
_Constellations_, to represent the, 101
_Cotton_, electrified, 92
_Cylinders_, of, 9
—— composition for lining, 125
—— plates may be substituted for, 14
D
_Dance_, electrical, 75
_Decomposition_ of water by electricity, 103
_Director, bottle_, description of, 65
—— use of, 67
_Discharging_ electrometer, description and use of, 67
—— rod, luminous, 103
_Du Fay’s_ theory of electricity, 109
E
_Electric attraction and repulsion_, 21
—— —— —— —— exemplified, 22, 24
—— battery and experiments with it, 28
—— eel, an account of the, 56
—— fly, described, 18
—— light, experiments with, 79
—— spark, 16
_Electric_ spider, 25
_——s_, and phenomena produced by them, 2, 3, 6, 8
—— experiments with charged, 86
_Electrical_ machine described, 9, 13
_Electricity_, the identity of with lightning, 40
—— how it may be applied to the best advantage, 65
—— animal, 55
—— apparatus necessary for, 64
—— atmospheric, danger of making experiments with, 42, 44
—— medical, 63
—— positive and negative, 2
—— various theories of, 108
_Electrometer_ described, 36, 64
—— instructions for using, 37
_Electrophorus_ described, 33
—— experiments with the, 34
_Excited_, what is intended by, 1
_Experiments_, practical rules for making, to the best advantage, 68
—— promiscuous, 94
_Explosion_, the lateral, 101
F
_Figures_ made upon glass &c. by means of electricity, 97
_Fountain_, the electrified, 104
_Fractured jar_, how repaired, 70
_Franklin, Dr. his experiment_ with a kite, 40
—— —— —— —— for illustrating his theory of thunder storms, 78
—— his theory of electricity, 116
_Friction_, electric, 65
G
_Gibbes Dr._ his theory of electricity, 113
_Glass_, metals forced into, by an electric explosion, 30
_Gun-powder_ fired by an electric explosion, 30
I
_Jack_, the electrical, 94
_Jar_, electrical, fractured, how repaired, 70
K
_Kite_, Dr. Franklin’s experiment with a, 40
—— _electrical_, structure and use of the, 41
—— —— Cavallo’s directions for using the, 43
L
_Lane’s_ discharging electrometer, 67
_Leyden phial_ described, 26
—— —— experiments with the, 27
—— vacuum, 81
_Light, electric_, experiment with, 79
—— —— flashing between two metallic plates, 83
_Lightning_, the identity of with electricity, 40
—— _rods_, the structure and use of, 48, 54
—— —— improved by professor Patterson, 51
_Luminous_ conductor, 82
—— to render various substances, 84
—— shower, 102
M
_Machine_, electrical, described, 9
_Magic_ picture, 86
_Magnetic needle_, effect of electricity on the, 31
_Medical_ electricity, 63
_Metallic oxyds_ revivified, 31
_Metals_ forced into glass by an electric explosion, 30
N
_Natural state_, meaning of, 2
_Nollet’s Abbè_, theory of electricity, 110
_Non-electrics_, 2, 7
O
_Oxyds_, metallic, revivified, 31
P
_Paint_, for electrical purposes, preparation of, 126
_Paper_ stained by an electric explosion, 31
_Picture_, magic, 86
_Pointed bodies_, their influence on electricity, 17, 92
—— —— phenomena attending, 17
—— —— conclusions respecting, 21
_Powder, gun_, fired by electricity, 30
_Prime-conductor_, 12
R
_Repulsion_, electrical, 21
_Richman_, Professor, killed by atmospheric electricity, while making experiments with it, 42
_Rubber_, defined, 2
—— described, and directions respecting it, 10
S
_Shower_, luminous, 102
_Snake_, electrical, 102
_Spark_, electric, 16
—— —— applied for curing deafness &c., 66
—— —— to render the, visible in water, 84
_Stream_ —— useful in curing diseases of the eye, 67
_Syphon_, the capillary, electrified, 100
T
_Terms_, explanation of, 1
_Thermometer_, effect of electricity on the, 32
_Thunder-house_, experiments with the, 54
_Torpedo_, an account of the, 58
—— artificial, to make, 60
_Tube_, spiral, 83
—— the self-charging, 95
V
_Vacuum_, what is meant by the term, 79
—— Leyden, 81
_Vegetables_, effect of electricity on, 61
_Velocity_ of electricity, 15, 29
W
_Water_ decomposed by electricity, 103
_Wheels_, multiplying, may be added, with advantage, to an electrical machine, 12
—— self-moving, described, 74
_Wilson’s_ theory of electricity, 109
_Wine_, spirit of, fired by electricity, 89
INDEX TO THE EPITOME OF GALVANISM.
A
_Animals_, cold blooded, best for Galvanic experiments, 131
_Arc_, animal, and excitatory, 132
B
_Berzelius_, his experiments, 147
C
_Conclusions_, 139, 143
_Conductors_, Galvanic, 133
_Cruickshank’s, Mr._ experiments, 140
D
_Davy Mr._ his experiments, 146
_Diseases_ in which Galvanism has afforded relief, 156
E
_Effects_, common, supposed to be occasioned by Galvanism, 150
F
_Frogs_, Galvanic experiments upon, 138
—— —— —— —— conclusions drawn from, 139
G
_Galvanism_, a short account of, 129
—— medical, 154
—— identity of, with electricity, considered, 157
L
_Light_, Galvanic, to exhibit, 148
M
_Metals_, most suitable for Galvanic experiments, 132
—— on the deflagration of, by the Galvanic pile, 143
P
_Pile, Galvanic_, description of the, 134
—— —— experiments with the, 140, 143
—— —— its two extremities in opposite states, 146
_Pontin Mr._ his experiments, 147
T
_Trough, Galvanic_, description of, 136
—— —— experiments with the, 146
V
_Vegetables_, effects of Galvanism on, 152
W
_Water_, the taste of, affected by the Galvanic influence, 149
-----
Footnote 1:
Apuleius, Floridor, page 361.
Footnote 2:
Theophrast. περι λιδων.
Footnote 3:
Dr. Falconer, in a paper inserted in the “Memoirs of the Manchester Society,” has endeavoured to prove by quotations from the writings of antiquity, and by much ingenious reasoning, that the ancients were not only acquainted with the electrical shock, but that it is probable even the method of drawing down lightning from the clouds, was known in very early times, and particularly to Numa Pompilius, the second king of Rome; and that his successor Tullius Hostilius perished, by his unskilful management of so dangerous a process.
Those who wish to pursue this subject, we refer to the above mentioned paper in 3 vol. Memoirs of the Literary and Philosophical Society of Manchester, page 378.
The same opinion is ingeniously defended, in a work of M. Dutens, entitled, “Origine des Decouvertes atribuees aux Modernes.” Some curious quotations from the ancients, on electricity, are likewise contained in the Gentleman’s Magazine for July 1785, page 522.
“To these may be added a curious passage in Signor Boccalini’s advertisement from Parnassus (century 1. chap. 46,) published more than a hundred years before the date of Franklin’s discovery, and in which the identity of the electric fluid and lightning is said to be revealed.” Miller’s Retrospect, 1 vol. page 24.
But after attentively considering all these discoveries, we cannot help acceding to the opinion of the learned President Gouget, a man who had most thoroughly investigated the origin of science among the ancients, and we are fully persuaded that what he says of several other subjects is precisely the truth in regard to electricity.—“All (says he) which we read on this subject in the writings of the ancients, ought to be regarded as mere ideas advanced at random, without knowledge, without principles, and without any kind of foundation. If some of the ancients, for example, have said, that the earth was a spheroid, flattened at the poles; that it revolved round the sun; that the comets were planets, whose periodical revolutions were completed in a certain number of ages; that the moon might be habitable; that that planet was the occasional cause of the flux and reflux of the sea, &c.; we ought not to regard these propositions in their mouth, as the effect and the result of the knowledge which these philosophers had acquired. On the contrary, we ought to place them on the footing of those hypotheses which an uncertain and ill-regulated imagination daily produces. I say so, because none of the ancient philosophers have been able to give reasons for what they delivered; which we may be easily convinced of, by reading the manner in which the writers of antiquity relate the opinions of their learned. There we see, that the ancients had no reasons preponderating to adopt one system rather than another; neither were they ever able to give any of them the slightest demonstration. For the rest, I do not pretend to make this a matter of reproach to the ancients. They were destitute of all helps proper to acquire these branches of knowledge. If, nevertheless, they have sometimes hit upon the truth, we ought to attribute it to pure chance; and be sensible, that, as they wavered in uncertainty, and ran through all possible combinations, it is not astonishing that they should hit upon the true one, because the number of these sorts of combinations is not infinite. In this respect consists the characteristical difference between the astronomical learning of the ancients and that of the moderns. What at this time we affirm of the figure of the earth, of the system of the heavens, of the cause of the flux and reflux of the sea, &c. is not the effect of chance and imagination; it is the result of much observation, experience, and reflection, and every astronomer is able to support by reasons the system which he has thought fit to embrace.”
_Origin of Laws, Arts, and Sciences_, Vol. III, Book III, Chap. II, Article IV.
Footnote 4:
Bayle in Vita Aristot.
Footnote 5:
Gilbert, De Magnete. Lib. 2, Cap. 2.
Footnote 6:
Philos. Trans. abridged, Vol. 7, page 18.
Footnote 7:
The author of the article Electricity in the Encyclopædia, ascribes the merit of this discovery (if any merit can arise from a discovery made by accident) to Mr. Van Kleist, dean of the cathedral of Camin. On what authority he does this, we are unable to state. The following (he says) is the account of it, which the dean, on the 4th of November 1745, sent to Dr. Leiberkulm at Berlin, “When a nail, or a piece of thick brass wire, &c. is put into a small apothecary’s phial, and electrified, remarkable effects follow: but the phial must be very dry, or warm. I commonly rub it over before-hand with a finger, on which I put some pounded chalk.—If a little mercury or a few drops of spirit of wine are put into it, the experiment succeeds the better. As soon as this phial and nail are removed from the electrifying glass, or the prime-conductor to which it hath been exposed is taken away, it throws out a pencil of flame so long, that with this burning machine in my hand, I have taken above sixty steps in walking about my room. When it is electrified strongly, I can take it into another room, and there fire spirits of wine with it. If while it is electrifying I put my finger, or a piece of gold which I hold in my hand, to the nail, I receive a shock which stuns my arms and shoulders.”
“A tin tube, or a man, placed upon electrics, is electrified much stronger by this means, than in the common way.—When I present this phial and nail to a tin tube, which I have, fifteen inches long, nothing but experience can make a person believe how strongly it is electrified. Two thin glasses have been broken by the shock of it.”
Footnote 8:
Such is the statement usually given. It may perhaps deserve consideration whether _the cause_ of this luminous spark or stream, should not, strictly speaking, be considered as the true electricity.
Footnote 9:
Tourmaline is a species of silicious earth. Its colour is generally a blackish brown, though the tourmaline of Brazil is blue, green, red, or yellow. It is a compound substance, consisting of argill, silex, calcareous earth, and iron in different proportions; but argill and silex are always the chief ingredients. It is found in Ceylon, Brazil, and Tyrol; and it is also found in large quantities in the neighbourhood of Philadelphia, attached to masses of quartz.
Footnote 10:
It is very remarkable that the focus of a burning glass is not a conductor of electricity.
Footnote 11:
We do not wish to be understood that _two different_ fluids may be produced, but merely, that the prime conductor may be electrified _positively_ or _negatively_.
Footnote 12:
For the proper cement, see appendix NO. I.
Footnote 13:
See appendix NO. II.
Footnote 14:
See appendix NO. III.
Footnote 15:
This consists of two small balls of cork or pith, fastened to the ends of a thread or piece of silk. When it is to be used the thread or silk must be held by the middle so that the balls may hang close to one another.
Footnote 16:
Mr. Richman, professor at Petersburg, was killed on the 6th of August, 1753, by the lightning which he had drawn into his room, for the purpose of making experiments. The circumstances of this interesting and instructive occurrence were the following.