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and fications of clouds.
e | Thermometer.
strong Flocculent masses positive Moderate divergence generally. breeze of cirrus cloud,
Pendulums strike when a S.W. with ragged pim
nimbus reaches zenith of apbus at times, from
of which large rain
catarrh and bronchitis occur drops are occasion.
at this time. ally discharged.
28 61 29.53 gusty, Nimbus with inter- positive Occasional slight divergence.
vening haze. 11,30 a.m constant Continued fine rain
No evidence of electric action. strong and drizzling haze.
breeze. 29 64 29.40 strong Sudden rain squalls. positive Torrents of brilliant sparks breeze
during incident to the rains; atmoand occa
rain. sphere neutral in the insional
S.W. 30 67 29-65 breezes, Blue sky with cirro neutral Sensation of langour and opW. cumulus, &c.
pression, with pungent heat
of the soles of the feet. breeze Gentle rains. positive Feeble current faintly visible variable.
by daylight, and appearing as a luminous brush; stream of small sparks occasionally.
The average condition of the atmosphere in this locality has been apparently highly favourable to health, throughout the month. Cases of scarlatina, cynanche, &c., which commenced about the 9th inst., assumed a mild form, and readily yielded to the usual treatment.
The various ramifications of cirri, and occasionally the several modifications of cirro-cumulus, have, especially in the fine evenings, presented several highly-beautiful pieces of sky, in which it was obvious that the great agent of the universe, electricity, was performing an active part.
During the nights of the 7th, 14th, 18th, 19th, 27th, and 30th, many small lucid meteors made their appearance, passing mostly at or near to a right angle with the magnetic meridian.
On Professor Pfaff"s Theory of Galvanism. In a Letter to Pro
fessor Palmstedt, of Gottenburg, from Professor J. BERZELIUS, of Stockholm. Dated October 9th, 1841.*
Dear Friend, -I suppose that I, in my last letter to you, forgot to mention a remarkable scientific notice which I received by a letter from Professor Pfaff, of Kiel. You are aware that he has for a long time been engaged in the attempt of deciding the question, whether the contact of the metals, or the chemical effect of the liquor, be the primary action in developing the electricity of the pile. He has invented a hydro-electric pile, in which the metals are not affected by the liquor, and where no apparent chemical decomposition into its component parts is taking place, even when the phenomena of electricity are from 30 to 40 times more intense than by a pile, of equal magnitude and form, of copper, zinc, and diluted sulphuric acid. Fig. 8, plate 1, represents a horizontal section of this pile; where a is, an open cylinder of china covered with platinum, like those of the many a year ago used tea-pots; b is a cylinder of burned, porous, unglazed china, furnished with a bottom; ca cylinder of amalgamated zinc, open throughout; and d a cylindrical vessel of glazed china, or of glass. Into b concentrated nitric acid is to be poured, and into d a saturated solution of sulphate of zinc, which will here have a stronger effect than sulphuric acid diluted with one-tenth of water. The combination of the different pairs is made like that of Professor Bunson. The action was found to be continuous up to 48 hours, when he wrote to me, and no gas had issued from the surface of the zinc, nor had any oxydated zinc been precipitated in the liquor. He considered this phenomenon as an experimentum crusis, proving the theory of electrical contact, and he supposes that this construction of the pile may be of practical use, if the electro-magnetism is to be turned to advantage as a motive force. As to this new electrical instrument, Professor Pfaff may be mistaken in his assertion that a chemical decomposition is not taking place; because, according to all theories, it will follow, but by different phenomena from those which take place when the zinc is exposed to a free acid.
A zinc salt will arise on the metal, and, corresponding to the oxyde of the zinc, will be collected in the nitric acid; which, probably, will at length contain a great deal of nitrate of ammonia and nitrate of zinc ; and the experiment will then only show that no greater corrosion of the zinc is taking place than what will be equal to the electric current.
Concerning the theoretical value of this pile, it would decide nothing, even if the question had not been decided a long time before by Professors Poggendorff and Fechner's Researches. Those
* This letter was kindly handed to us by Richard Roberts, Esq., C. E., of Manchester, who had it direct from Professor Palmstedt.-Edit.
who attempt to decide it in the hydro-electrical way, will for ever be in a dispute, without coming to a final satisfactory conclusion ; because the electrical current and chemical decomposition will always be found quite inseparable. It is alone by the dry way that an experimentum crusis is to be obtained, and will be obtained, in spite of the capricious phenomena of oxydation which have been ascribed to the dry way. The dry electric piles that I brought home in 1819, and which then were many years old, are still, after a lapse of twenty years that I have had them, as powerful as when I first got them. The metals which form them are leaves of tin and brass, so thin as scarcely to be measured ; yet these have produced an electric action for twenty-two years, and instead of being oxydized through, are still perfectly metallic. You see, therefore, that this scientific dispute is thus carried on; that some of the persons interested in it do not lay their questions quite impartially to nature. How is it?' They are looking continually for arguments in favour of an hypothesis which they consider to be the right one. They will always be found in a situation very disagreeable to the true lovers of science, not being able to be fully persuaded to the facts of the contrary party, pleading to hypothesis instead of refutations by real facts. The former party will be placed without the limits of facts, and thus they will always shew an apparent irrefragibility, although they cannot disprove the facts on the other side of the question.
This question will never be ended until the last champion of the wrong supposition has ended his earthly career; then truth will remain triumphant and uncontested.
Please to excuse me if I have too long detained you by presenting my own views on Professor Pfaff's experiment.
Experimental and Theoretical Researches in Electricity, Magnetism,
fc. By WILLIAM STURGEON ; prior to his establishing " The
Annals of Electricity, &c." After leaving the service of the Royal Artillery, in 1820, and as my slender finances presented opportunities, I turned my attention to experimental inquiries, and to the construction of some of those philosophical apparatus which, from boyhood, I had been an admirer of, but of which, during my services at least, a military profession precluded all further knowledge than that which was to be learned from books of science, a species of commodity, at that time, exceedingly rare in the army, even in the distinguished branch to which I belonged.
The first piece of my apparatus which found its way scientific journal, was a modification of Ampere’s rotating cylinders, as improved by Mr. Marsh. This apparatus was disposed of to Mr. Jones, optician, Holborn, who sent it to the United States. Mr. Jones was kind enough to draw up the following short account of it, and got it introduced to the pages of the Philosophical Magazine for September, 1823 :-“The apparatus consists of two
sets of revolving cylinders, one suspended on each pole of an inverted horse-shoe magnet,* as represented by fig. 1, plate 3. Upon the usual insertion of the diluted nitric acid, the two sets of cylinders simultaneously enter into rotations in a very interesting and striking manner. This form of the magnet gives increased power on a reduced altitude, and the proximity of the poles materially augments the rotation of the opposed cylinders. The effect is the most pleasing we have ever seen, and was witnessed at the house of Messrs. Jones, opticians, Holborn.” The appearance of this apparatus was much improved by the outer cylinders and base being made of brass.
Prior to this apparatus making its appearance, a straight bar magnet was invariably employed to shew the action of Ampere's cylinders: the action was first shewn on oue pole, and then the magnet inverted, to shew the action on the other pole.--Edit.
Electro - Magnetical Experiments. By William STURGEON.
To the Editors of the Philosophical Magazine and Journal. Being desirous to understand the relation that subsists between the chemico and thermo-electric phenomena, as influenced by the magnet, so as to form a comparison of the widely different apparatus for exhibiting those phonomena ; and likewise, if possible, to ascertain some general law to be observed in thus comparing the two modes of exciting this influence; the few following simple experiments suggested themselves as the most likely to give satisfaction on this point. As this investigation and comparison* seems to have escaped the attention of every other experimenter, perhaps a detail of those experiments, with their results, and a description of an instrument which I have been led to invent and construct, upon a simple principle, for the purpose of carrying on the comparison to any required extent, may not be thought uninteresting to some of your readers.
Exp. 1. I charged in the usual way, with dilute nitric acid, an Ampere's rotating cylinder, and placed it on a table. I now placed the north pole of a bar magnet on the upper edge of the outer rim of the copper part of that apparatus. I likewise imagined myself “coinciding in position with the wire about which the machine turns,” and “looking towards the magnet.” On bringing one of the wires of the zinc cylinder between me and the magnet, that wire was projected to the left.
Let the line E D, fig. 2, be the horizontal part of the wire in this and the following experiments, moveable on a pivot o; then, when the wire is said to be projected to the right, it is meant that the point E is projected towards R, as oR; and when to the left, the point E is projected towards L, as o L.
Exp. 2. I now presented the south pole of the magnet to the wire. The latter was projected to the right.
Observation. This chemico-galvanized wire was evidently the
There may be said to be one objection; for a comparison has certainly been made by a philosopher of acknowledged skill; and it is with due deference that I cannot subscribe to the conclusions of that gentleman.
ascending wire from the zinc to the copper; or (which is the same thing) the descending wire from the copper to the zinc.
Exp. 3. I now suspended, by a piece of untwisted silk, a semicircular copper wire, with a zinc diameter, as in fig. 3; ccc is a fine copper wire; and zzz a fine slip of zinc, soldered to the former at the extremities zz. The north pole of the magnet was now placed close to one arm of the semicircular arc, as shown in the figure, and the lamp applied at E. The wire was projected to the left.
Exp. 4. The semicircle adjusted as before, the lamp was now applied at D. The wire was projected to the right.
Exp. 5 and 6. In these experiments the lamp was applied as before, but the south pole of the magnet was now presented to the wire. The motions were the reverse of the two former experiments.
I have tried rectangles instead of semicircles, but there is no difference in the results.
If a semicircle or rectangle be made of platinum and silver wires, the former supplying the place of the copper, and the latter be substituted for the zinc, in the above thermo experiments, the results of the two machines are exactly alike; hence the copper and platinum wires are possessed of the same kind of electricity, and so are the zinc and silver each to each, but of the contrary kind of the other two wires: so if the copper be positive to the zinc, by this magnetic test, we must necessarily conclude that the platinum is positive to the silver.
But this is not all that is to be observed in these experiments ; we must compare the results of the chemico with those of the thermo experiments, and endeavour to trace the relation that subsists in the phenomena exhibited by those two modes of exciting the electrical influence.
We will therefore compare our chemico experiment 1, with out thermo experiment 3. We here find the wire projected to the left in both cases.
We will now suppose the immersed plates of the chemico apparatus to correspond with the heated union of the thermo wires, and the most remote extremities of the chemico conducting wires with the coldest part of the thermo apparatus. It will follow, that as the copper wire (by the supposition) is as evidently ascending in the thermo machine, as the zinc wire is ascending in the chemico cylinder; and as they are both propelled in the same direction (left), by the approximation of the north pole of the magnet, the forces of the two galvanised wires must of necessity be exerted in contrary directions. For although they are both propelled the same way yet they are of contrary kinds or names.
Again. Let us now suppose the immersed plates of the chemico apparatus to correspond with the coldest union of the thermo wires, and the most remote extremities of the chemico conducting wires with the heated junction of the thermo machine. In this case, the two wires nearest the magnet of the chemico and thermo machines will in all respects correspond with each other; for they are now both descending from the copper, or both ascending from the zinc