pound, when different in mass, but proportional in all their dimensions, are not in the ratio of the masses, the large masses being less strong proportionally than the smaller. 3. That whilst magnets of large dimensions are less powerful with respect to their masses than small magnets to which they are exactly proportional in all their dimensions; and whilst the increase of the dimensions continually deteriorates from the energy due to the mass: yet magnets may be combined in such proportional dimensions with a constant increase of power ad infinitum. From this last result it follows, that magnets indefinitely small must be indefinitely strong; and may indicate that the mutually attractive forces of the ultimate magnetic elements may be as strong as that by which the metallic elements are themselves combined. It must also be kept in mind that the steel should be perfectly hard; and the elementary plates of the magnet should be made of steel, converted out of one or other of the very best qualities of common iron. All the conditions, with the exceptions of thinness, were attended to in the large magnet constructed by Dr. Scoresby. A magnet on this principle, of the size of the lower mast of a first-rate ship of war, would produce a deviation of nearly l' at the distance of a mile, and a sensible effect much beyond that. The electrical effects of Dr. Scoresby's magnet, with a very imperfect armature, were, it decomposed water, rapidly producing about one cubic inch of the gases a minute; with about sixty-five yards of coiled wire, the effervescence seemed as violent as during the action of dilute sulphuric acid or zink. Copper was deposited from a solution of sulphate of copper at the rate of about 1.2 grain per minute. Shocks

and scintillations were thrown out; and sparks were visible in daylight, and emitted audible sounds when the armature revolved so slowly as once in sixteen seconds.

Prof. FORBES had little doubt that Dr. Scoresby could construct very powerful magnets; but he thought that as electromagnets, so much more powerful, were so readily made, it was almost useless to incur the expense of the others.

Rain Gauges.

A paper was read "on the amount of rain which had fallen, with the different winds, at Toomavara, Limerick, during five consecutive years," by the Rev. T. KNOX. Taking the average monthly rain at three inches, the first six months of the year are below the average, the other, six months above it. November and July are by far the two wettest months in the year; and in each the greatest amount of rain is from S.W.

April is much the driest month; and there is nearly as much rain in it from the northern portion of the compass as from the southern. With regard to the gross amount which fell from each point in the entire year, that which fell from S., S.W., and W., is much above the average; from the other points it is below it. If the polygon which characterizes the yearly rain be divided by a line running N.E. and S.W., then the rain at equal intervals on either side of this line is equal, to all but a fraction of an inch. This is the more remarkable, as these two points had been fixed on by Professor Dove as being the points of greatest and least barometric pressure; that is to say, the wind being supposed at S.W., any shift of it either towards S. or W. produces a rise of the barometer, and also any shift on either side of N.E. a corresponding fall. Now, in the case of the rain, the greatest amount is from S.W., corresponding with the least height of the barometer; the least is from N.E., where also the barometer is highest; and on either side of this line it varies regularly. For instance, the amounts from W. and S. are nearly equal, and both less than that from S.W. N.W. and S.E. are also equal, but still less; and so on. There is one particular in which this separation of the gross amount of rain into the eight portions, as brought by different winds, may be useful; viz., in ascertaining the respective specific gravities, and the amount of saline matter brought from each direction. This may be useful in regard to agricultural matters. For instance, we could easily suppose a case of two portions of land, not many miles asunder, but on different sides of a high range of hills, getting different amounts of salt, from one being exposed to, and the other sheltered from that wind in which the greatest amount was found. But by this mode of collecting the rain, an accurate mode of estimating this is within our reach. To the question, namely, the amount of solid and gaseous matter brought in the rain from each direction, Mr. Knox hopes on a future occasion to turn his attention.

The tables which accompany this communication give the amount of the rain corresponding to each wind, for each separate month in the five years. The following are the yearly mean results, deduced from the whole series.

which mutually replace each other, a distinction is to be drawn between two kinds of rain, the one caused by refrigeration of the southern current coming into higher latitudes, the other when the southern current in the place of observation is overpowered and replaced by the northern. The first takes place when the vane is S. W., the latter when the vane passes from S.W. through W. to N., or from E. through S: to The direction N.E. indicates the S.W. polar stream without condensation. it follows, that the quantity of rain is a maximum at S.W., a minimum at N.E., and is distributed symmetrically on either side.

Hence

The Bishop of NORWICH expressed the satisfaction which he felt at hearing the communication of Dr. Lloyd, and his hopes that extended series of similar observations would soon be put on record. The great and anomalous varieties in the quantity of rain which fell in various localities would, he had no doubt, be found such as to create surprise. Thus, in London the quantity was only 23 inches annually, while in the neighbourhood of his residence it was no less than 33.-Sir JOHN HERSCHEL said that the importance of such observations, when well conducted, could scarcely be over estimated; he believed the discrepancy in the amount of rain which fell in several parts of England was still greater than had been stated by the Bishop of Norwich. If his memory did not deceive him-while in London the annual depth was only 23 inches, in Keswick it was no less than 60.-Mr. ROBERTS observed, that the discrepancies in the registries of rain-gauges were such as to render great caution necessary in drawing conclusions. It was now beginning to be understood that unless the rain-gauges were placed on a level with the earth, no indication would be obtained from them of the quantity which fell on the surface.-The Astronomer Royal said that there was something still unexplained as to the effect of the altitude at which the rain-gauge was placed, on the amount of rain received; while the quantity of rain received in the gauge on the top of the Observatory was less than that placed in the court below, yet a gauge placed at the foot of Greenwich Hill, which was at a considerably lower level than either, received less rain.-Sir J. HERSCHEL believed that the cold drop as it descended from above received accessions from the vapour of the air through which it passed; and if this be the true account, then the explanation was complicated by the relative hygrometric states and temperatures of the several strata of air.

Furnace Gases.

11

Voltaic Reduction of Alloys.

A paper on this subject, by Mr. C. V. WALKER, was read. It had for its object to explain the methods by which the author has succeeded in throwing down metallic alloys from compound solutions by the action of galvanic electricity. The process adopted is to prepare a strong solution of cyanide of potassium, and commence electrolyzing it, by means of a copper anode; as soon as copper begins to be dissolved, the copper anode is removed, and its place supplied with one of zink; after the action has continued for some little time, brass will be liberated on the cathode. The solution is now ready for use, and is operated upon by two or three Daniell's cells, and with a brass anode. By similar means alloys of gold and copper, or gold and silver, may be deposited. The author reasons,

that true brass is a definite chemical compound; and observes, "It appears possible that the anode, which is a brass of commerce, is a true alloy, plus an excess of zink; that the solution it produces is a

mixed solution, which consists of the potassiocyanide of brass and the potassio-cyanide of zink. The solution is very readily decomposable; it is therefore necessary to prepare it a short time previously to its use." Many specimens were exhibited of copper and other metals coated with brass. The author makes some remarks on the theory of the action; and concludes by stating that it will be quite possible to determine, within certain limits, the character of the alloy that shall present itself, and that we may be enabled to throw down gold and silver according to standard.

Experiments on the Spheroidal State of Bodies, and its Application to Steam-boilers, and on the Freezing of Water in red-hot Vessels.

A paper under this title, by Professor Boutigny, was read and illustrated by experiments. The Professor commenced by showing that when cold water is poured on a hot metallic surface, the heat is not communicated to it; and that the water assumes a spheroidal form, and continues to roll about, upheld at a minute distance from the heated surface, without boiling. The water poured into a heated platinum cup kept in rapid motion, and resembled a small globe of glass dancing about. There was no hissing noise nor appearance of steam, though the globule of water must, nevertheless, have evaporated rapidly; for, after gradually diminishing in size, in the course of about two minutes it disappeared. The same result takes place when any substance capable of assuming a globular form is placed on a heated surface. In proof of this, the Professor placed in the heated cup of platinum, iodine, ammonia, and some inflammable substances; each of which became globular, and danced about like the globule of water, but without emitting vapour or smell, or being inflamed, until the platinum cup was cooled. Another experiment was yet more curious. Professor Boutigny heated a silver weight, of the same shape as the weight of a clock, until it was red-hot; and then lowered it by a wire into a glass of cold water, without there being the slightest indication of action in the water, more than if the weight had been quite cold. Professor Boutigny advanced no theory to account for these peculiar actions, further than that a film of vapour intervenes between the heated body and the substance, which prevents the communication of heat. The facts, however, he thought were of importance in a practical point of view, both as regards the tempering of metals, and in the explanation of the causes of steam-boiler explosions. It would seem from these experiments, in tempering metals,

that if the metal be too much heated, the effect of plunging it into water will be diminished. In steam-boilers also, if the water be introduced into a heated surface, the heat may not be communicated to the water, and the boiler may become réd hot, and without any great emission of steam; until at length, when the boiler cools, a vast quantity of steam would become suddenly generated, and, the boiler burst. The last and most curious experiment performed by Professor Boutigny was the freezing of water in a redhot vessel. Having heated a platinum cup red-hot, he poured into it a small quantity of water, which was kept in a globular form, as in the other experiments. He then poured into the cup some liquid sulphurous acid; when a sudden evaporation ensued, and, on quickly inverting the cup, there came out a small mass of ice. This experiment called forth loud and continued applause. principle on which this experiment depends is this-sulphurous acid has the property of boiling when it is at a temperature below the freezing point; and when poured into the heated vessel, the suddenness of the evaporation occasions a degree of cold sufficient to freeze water.

The

DR. W. G. TURNER'S PATENT METHOD OF PURIFYING THE VAPOURS OF CHEMICAL WORKS.

Dr. Turner's patent (dated August 22, 1844, specified February 8, 1845,) is for an improved method of directing the passage of, and otherwise dealing with, noxious vapours, and other matters arising from chemical works in certain cases. ""

The nature of this invention consists in the application of certain mechanical contrivances to produce a draught in the manufacture of sulphuric acid, muriatic acid, and sulphate of soda, and to the roasting and smelting of metallic ores, in aid of, or as a substitute for, the ordinary draft of a chimney; by which contrivances, together with certain improved processes, that portion of the acid gases and metallic fumes are condensed, which, in the methods now employed, escape into the atmosphere. Moreover, the products obtained from a certain quantity of materials are stated by this invention to be considerably increased, while the causes of injury to vegetation, &c. are completely removed.

The apparatus by which the object of this patent is effected, consists of a horizontal

For the first account published in England of this remarkable experiment, see Mechanics' Magazine, vol. xli. p. 23.

13

vessel, which may be of sheet iron, fire-
brick, or stone, according to the corrosive or
non-corrosive nature of the substances em-
ployed therein. In this vessel is placed a
continuous screw, made of suitable materials,
and revolving on an axis, which is connected
with a steam-engine, water-wheel, or other
moving power, in such a manner as to cause
the screw to revolve with great rapidity,
and thereby to produce the requisite draft,
the threads or vanes of the screw being
made of considerable width for that purpose.
Upon the shaft of the screw, and at certain
intervals along its length, are placed long
arms, projecting perpendicularly from the
shaft to distances nearly equal to the thread
of the screw.
The vessel in which the screw
revolves is then connected with the furnace
from which the fumes are emitted by means
of a flue, and a quantity of water is allowed
to enter the vessel by means of a feed-cock,
so as to cover the lower edge of the screw
to the depth of three or four inches, the
lower part of the vessel forming a trough for
the water, from which, by means of a suit-
able tap, it may be abstracted at pleasure.
The arrangement being thus effected, the
screw is put in motion up to a speed com-
petent to produce the requisite draft in a
direction from the furnace; at the same
time the water in the vessel is worked by
the action of the screw, and violently dashed
and broken, by the arms projecting from the
shaft, into a mass of foam and spray, which
wets the fumes by beating them about with
the water in their passage through the ves
sel, until they become too heavy to pass on
with the draft, when they descend to the
bottom of the trough. When this apparatus
is applied to the condensation of lead, or
other metallic fumes, the water must be
drawn off from time to time, into proper
tanks or receivers, in which, by standing,
the metals are deposited.

When this invention is applied to the ⚫ manufacture of sulphuric acid, the patentee avails himself of the aid of such condensing agents as the acid gases have an affinity for ; and in order to this, he employs a series of air-tight vessels, called condensers, which should be made of wood, and lined with lead, and strong enough to bear a considerable pressure. In one of the condensers with which the draft pipe is connected, a quantity of what is usually called chamber acid is admitted, so as to cover the opening of the draft pipe from the sulphuric acid chamber to the depth of two or three feet. The upper part of this condenser is then connected with air-pumps of sufficient power and capacity to draw through 162,000 cubic feet of air for every hundred pounds of sulphur burnt, and to cause a partial

"

vacuum to be made and maintained in the upper part of this condenser. By this arrangement, the gases from the sulphuric acid chamber force their way in a continuous stream through the acid in the condenser, and thus cause a draught from the sulphuric acid chamber.

For the better understanding of this invention, it must particularly be remarked, that there are three causes which operate to produce the loss of nitre in the common method of manufacturing sulphuric acid; which causes of loss are stated to be entirely prevented, or at least greatly diminished, by this improved draft, and mode of dealing with the noxious vapours. The apparatus and processes by which these objects are effected are fully described in the specification; but being too long to admit of a brief and perspicuous analysis without reference to the drawings, we think proper to conclude by merely stating the objects of the claim, which are ranged under five different heads, as follows::

Se

Firstly, the application of a screw and arms working in water, the one for the purpose of creating and increasing the draft, and the other for wetting and condensing the noxious vapours proceeding from furnaces in which the roasting and smelting of metallic ores are being carried on. condly, the application of the screw, or of airpumps and condensers, in the manufacture of sulphuric acid, muriatic acid, and sulphate of soda. Thirdly, the substitution of nitric acid to the sulphuric acid, in the acid chamber, for nitre in the furnace. Fourthly, the substitution of a shallow sulphuric acid chamber, instead of the deeper one hitherto in use, to prevent the formation of the crystalline compound of sulphuric and hyponitrous acids therein. And fifthly, the working the vapours in, and escaping from the acid chamber, through the condensers, - with the condensing media or agents.

FRENCH PATENT LAW CASE.

Tribunal Correctionel de la Seine, June 6, 1845.

M. Perrot, President.

MM. Christofle and Co. v. M. Bertrand.

The plaintiffs have a license to use MM. Elkington and Ruolz's patents for electrogilding and plating; and have already maintained several actions. The present action occupied the tribunal during four sittings; and is interesting both in respect to the

For the translation of this Report we are indebted to the last Number of Mr. C. V. Walker's valuable Periodical, The Electrical Magazine.

questions which it raises, and to the developments which it has given of the respective pretensions of individuals.

The following are the facts :

Several seizures were made, at the request of M. Christofle, in the workshops of one Bertrand, a gilder; and a jury of three, MM. Chevalier, Barrel, and Henry, appointed by the magistrate who has this affair in hand, have drawn out a detailed report of the objects seized, and placed it on the rolls of the court. Their opinion is favourable to the patentees.

M. Emanuel Arago opened the case for the plaintiffs, by detailing the affair, and commenting on the report of the jury.

M. Marie, on the part of the defendant, put forth three propositions, and gave evidence in support of them :

:

1st. There was no invention of galvanic gilding, either on the part of Mr. Elkington or of M. de Ruolz; and consequently their patents cannot be regarded as valuable. In support of which, he cited the chemical labours of Brugnatelli,* and De la Rive,† and a publication by M. Louyet, of Brussels. Brugnatelli and De la Rive had discovered the principle of the new gilding; and this principle, in his opinion, contains the germ of all the ulterior labours of MM. Elkington and De Ruolz, which ought to be considered as simple applications, of a more or less happy kind, but not patentable.

2nd. Supposing that there was an invention, and that the patents were valid, M. Bertrand cannot be condemned for infringement; for before the patents were taken out, he gilt by the same processes that are now in use; he ought to enjoy the benefit of the anterior possession. In support of this, M. Marie presented to the Tribunal numerous attestations in proof that, before the patents were taken out, M. Bertrand had gilt objects that could not be gilt by the old process, such as filigrees and solderings of tin; he also put forth invoices proving that, before the patents, M. Bertrand bad purchased certain chemical products, and especially the cyanides, the useful application of which to galvanic gilding had afterwards been pointed out by MM. Elkington and De Ruolz. And, according to the learned counsel, M. Bertrand is not the only one who had employed these substances anterior to the patent. M. Perrot, of Rouen, has just published a pamphlet, in which he maintains having gilt

with the cyanides before the patents were out.*

im

3rd. In the next place, the report of the jury cannot serve as the ground for an mediate solution; and this for several reasons,-first, because it says nothing in a precise manner on the question of novelty, and then, because it is ex parte; if it is ex parte-if M. Bertrand would not assist the operations of the jury; it is because, in his opinion, the questions were not well put by the magistrate. A second report is therefore necessary; and a fresh jury ought to be named. He here gave a critical examination of the report, which appeared to him incomplete, and by no means conclusive.

M. Emanuel Arago, in reply, said that he could not comprehend how the discovery of MM. Elkington and De Ruolz could be denied, to whom the Academy of Sciences had awarded two grand Monthyon prizes, upon the report of M. Dumas, as one of a commission, consisting of MM. Thenard, Darcet, Chevreul, Pelouze, and Pelletier. In order that the defence be admissible, we must admit that all these philosophers were ignorant of the labours of De la Rive. Now, this same commission that decreed a prize of 8000 fr. to Mr. Elkington, and another of 8000 fr. to M. De Ruolz, had given M. De la Rive a prize of 4000 fr., in recompense for the discovery of

* We give the following extracts from M. Per, rot's pamphlet, entitled, "Machine LithographiqueMachine à Imprimer les Etoffes et Dorure Galvanique," published by Lange, Levy and Co., Paris, 1844.

"1805. BRUGNATELLI.-The first idea of gilding by the galvanic pile is traced to Brugnatelli. He states his having gilt silver medals with a pile of several elements.†

"1840.-M. DE LA RIVE.-This learned philosopher gilds silver, copper, and brass with chloride of gold, by means of a galvanic apparatus of a single element. The piece to be guilt forms the negative pole of the single element.

1840, August, M. PERROT.-I obtain on gold, silver, copper, and on eyery oxidizable metals, such as iron and steel, very fine gildings, without the interposition of any metal. Not any of these gildings could hitherto be obtained, except by the employment of the battery and the alkaline cyanides.

"1840, September. MR. ELKINGTON.-He demands a further patent (brevet d'addition, Fr.,) in which he appropriates M. De la Rive's process. But, instead of dissolving the gold in chlorine, he uses prussiate of potash (alkaline cyanides); and he replaces the bladder used by M. De la Rive by porous earth, as has been long the practice in electrotype.

"1840, December 15. M. DE RUOLZ-He proposes to cover silver objects with a film of copper, so as to render them fit to be gilt by M. De la Rive's process."

"To one part of the saturated solution of gold in nitro-muriatic acid, add six parts of solution of ammonia, by which the solution is decomposed, and oxide of gold is precipitated, and a portion is set free, forming ammoniuret of gold."-Brugnatelli's gilding solution, extracted by Editor Elec. Mag., from Zantedeschi's Elecricity, vol. ii. p. 468.