scholarly journals I. The Bakerian Lecture. - On certain phenomena of voltaic ignition and the decomposition of water into its constituent gases by heat

1847 ◽  
Vol 137 ◽  
pp. 1-16 ◽  
Keyword(s):  
General Practice ◽  
Nitric Acid ◽  
Glass Tube ◽  
Platinum Wire ◽  
Pure Oxygen ◽  
Philosophical Magazine ◽  
The Wire ◽  
Decomposition Of Water ◽  
At Will

In the Philosophical Magazine for August 1841, I recommended for eudiometrical purposes, the use of a platinum wire ignited by a voltaic battery. In Plate I. fig. 1, is represented a form of apparatus for this purpose; it consists of a tube of Bohe­mian glass, with a loop of platinum wire 1/80th of an inch diameter sealed into its upper end; the size of the glass tube may be adapted to the quantity of gas sought to be analysed, and may when necessary be reduced to extremely small dimensions, one-eighth of an inch being ample; into this the gas may readily be made to ascend, by the insertion of a wire of copper, platinum, or glass, as may be suitable to the gas: two cells of the nitric-acid battery are sufficient fully to ignite the wire, and the same battery supplies, by electrolysis, pure oxygen and hydrogen for the analysis. Since the period when I first proposed this, I have seldom used any other apparatus for such gaseous analyses as are performed by combining the gas to be examined with oxygen or hydrogen. This eudiometer possesses the advantage of enabling the operator either to detonate or slowly to combine the gases, by using different powers of battery, by interposing resisting wires, or by manipulation alone, —a practised hand being able by changing the intervals of contact to combine or detonate the gas at will. My general practice has been to produce a gentle heat in the wire until the gases con­tract, and then gradually to increase the heat until a full ignition takes place, by which means all the objects of the eudiometer of Volta are fulfilled, without detona­tion, without dependence on the fickle electric spark, and without thick tubes, any danger of explosion, or of the gases being projected from the eudiometer. I have commenced with a description of this eudiometer, as it has been indirectly the means of my undertaking the experiments detailed in this lecture; and as its very great convenience has never been generally understood, I think that in strongly re­commending it, I shall be of service to chemists.

scholarly journals Bakerian Lecture—On certain phenomena of voltaic ignition, and on the decomposition of water into its constituent gases by heat

1851 ◽  
Vol 5 ◽  
pp. 657-659
Keyword(s):  
Carbonic Acid ◽  
Glass Tube ◽  
Platinum Wire ◽  
Philosophical Magazine ◽  
Decomposition Of Water

The author refers to an eudiometer, an account of which was published by him in the ‘Philosophical Magazine’ for 1840, formed of a glass tube, into the closed extremity of which a loop of plati­num wire was sealed. The gases to be analysed were mixed in this tube with a given volume of oxygen and hydrogen, and detonated or slowly combined by the voltaic ignition of the platinum wire. He was thence led to try a further set of experiments on the analysis, by this instrument, of such gases and vapours as are decomposable by heat; the process being capable of much greater exactness than the received one of passing them through ignited tubes. The re­sults of the analyses of several gases by this means are given in the paper. When carbonic acid and hydrogen are mixed in equal volumes and exposed to the ignited wire, the hydrogen abstracts oxygen from the carbonic acid, and leaves carbonic oxide. Con­versely, when carbonic oxide is exposed over water to the ignited wire, it abstracts oxygen from the aqueous vapour, and forms car­bonic acid. It thus appeared, that provided there were bodies present capable of absorbing by affinity the elements of water, ignited platinum would either compose or decompose water. The author was thence led to hope that he might by ignited platinum decompose water into its constituents, without absorption by other bodies, and thus pro­duce converse effects to those already known. In this he ultimately succeeded by various methods, in some of which the ignition was produced by electrical means; in others by ordinary calorific pro­cesses, such as the oxyhydrogen blowpipe, &c.

On the effect of surrounding media on voltaic ignition

1851 ◽  
Vol 5 ◽  
pp. 783-784
Keyword(s):  
Platinum Wire ◽  
Philosophical Magazine ◽  
The Wire ◽  
The Difference ◽  
Different Gases

The author refers to some experiments of his published in the Philosophical Magazine for December 1845, and in the Bakerian Lecture for 1847, relating to the difference of ignition generated in a platinum wire heated by the voltaic current, when the wire is immersed in atmospheres of different gases. In the present paper these experiments are continued, the current being passed through two platinum wires both in the same voltaic circuit, but immersed in atmospheres of different gases. It appears from these experiments that the heat generated in the wire is less in hydrogen and its compounds than in other gases; and that when the wires and their atmospheres of gas are immersed in given quantities of water, the water surrounding the hydrogenous gases is less heated than that surrounding those which contain no hydrogen.

scholarly journals Some researches on flame

1833 ◽  
Vol 2 ◽  
pp. 59-61 ◽  
Keyword(s):  
High Temperature ◽  
Glass Tube ◽  
Platinum Wire ◽  
The Wire ◽  
Humphry Davy ◽  
Lower Temperature ◽  
Sulphuretted Hydrogen

This communication is subdivided into four sections, of which the first treats of the effect of rarefactions of the air, by diminished pressure, upon flame, and explosion. An inflamed jet of hydrogen was placed in the receiver of an air-pump, and the flame was observed to enlarge during exhaustion, till the gauge indicated a pressure of one fourth or one fifth; it then diminished in size, but was not extinguished till the pressure was reduced to between one seventh and one eighth. A somewhat larger jet burned until the rarefaction amounted to one tenth, and rendered the glass tube whence the gas issued white hot. To this circumstance the author refers the long-continued combustion of the gas, and thinks the conclusion confirmed by the following experiment. A platinum wire was coiled round the jet tube, so as to reach into and above the flame, and it became white hot during the exhaustion, and continued red hot even when the pressure was only one tenth. The lower part of the flame was now extinguished, but the upper part in the contact of the wire continued to bum till the pressure was reduced to one thirteenth. The flame, therefore, of hydrogen is extinguished in rarefied atmospheres, whenever the heat it produces is insufficient to communicate visible redness to platinum wire. Sir Humphry Davy was thus led to infer, that those combustibles which require least heat for combustion would burn in rarer atmospheres than those requiring more heat; and that bodies which produce much heat in combustion would burn in rarer air than those producing little heat, and experiments are detailed proving this to be the case: thus, an inflamed jet of light carburetted hydrogen, which produces little heat in combustion, and requires a high temperature for its ignition, was extinguished whenever the pressure was below one fourth, even though the tube was furnished with a wire. Carbonic oxide burned under a pressure of one sixth; sulphuretted hydrogen of one seventh. Sulphur, which burns at a lower temperature than any other ordinary combustible, except phosphorus, had its flame maintained in an atmosphere rarefied 15 times, and phosphuretted hydrogen was inflamed when admitted into the best vacuum of an excellent air-pump. The author next proceeds to consider the influence of rarefaction, produced by heat, upon combustion and explosion. A volume of air at 212° is expanded to 2·25 volumes. At a dull red heat its probable temperature then is 1032°, provided it expand equably for equal increments of heat.

V. On the effect of surrounding media on voltaic ignition

1849 ◽  
Vol 139 ◽  
pp. 49-59
Keyword(s):  
Hydrogen Gas ◽  
Platinum Wire ◽  
Philosophical Magazine ◽  
Atmospheric Air ◽  
Specific Heats ◽  
The Wire

In the Philosophical Magazine for December 1845, I pointed out a striking differ­ence between the heat generated in a platinum wire by a voltaic current, according as the wire is immersed in atmospheric air or in hydrogen gas, and in the Bakerian Lecture for 1847 I have given some further experiments on this subject, in which the wire was ignited in atmospheres of various gases, while a voltameter enclosed in the circuit yielded an amount of gas in some inverse ratio to the heat developed in the wire. It was also shown, by a thermometer placed at a given distance, that the radiated heat was in a direct ratio with the visible heat. Although the phenomenon was apparently abnormal, there were many known phy­sical agencies by which it might possibly be explained, such as the different specific heats of the surrounding media, their different conducting powers for electricity, or the varying fluency or mobility of their particles which would carry off the heat by molecular currents with different degrees of rapidity.

On the peculiar cooling effects of hydrogen and its compounds in cases of voltaic ignition

1851 ◽  
Vol 5 ◽  
pp. 789-789
Keyword(s):  
Platinum Wire ◽  
Simple Solution ◽  
Cooling Effects ◽  
The Wire ◽  
Decomposition Of Water

In this communication the author gives several theorems which he considers to be established by the experiments cited in a pamphlet which he published, entitled “The Non-decomposition of Water distinctly proved.” He then states, that when we apply the principle of these theorems to Mr. Grove’s discovery of the cooling properties of hydrogen, it will be found to admit of a most simple solution: “for instance, when the coil of platinum wire is connected with the poles of the electric battery, and the current is established, it is evident that the electric matter thus passed through the wire must escape at the contrary end (the air with which the wire is surrounded not being a conductor of electricity), and as the quantity of electric matter thus transmitted is considerable, and its exit from the wire confined but rapid, that commotion before noticed (in one of the author’s theorems) necessarily ensues and causes the ignition of the wire ; but when the coil of wire is immersed in hydrogen, which is a conductor of electricity, it is evident that the electric matter must be, at the same moment, abstracted or conducted from every portion of the wire, and consequently the commotion or rush of the electric matter at the extremity of the wire, which causes the ignition, is suspended and the comparative coolness of the wire is the necessary result.”

III. Spectroscopic studies on gaseous explosions. No. I

1883 ◽  
Vol 36 (228-231) ◽  
pp. 471-478
Keyword(s):  
Glass Tube ◽  
Spectroscopic Studies ◽  
The Other ◽  
Platinum Wire ◽  
Iron Tube

Having occasion to observe the spectrum of the flash of a mixture of hydrogen and oxygen fired in a Cavendish eudiometer, we were struck by the brightness, not only of the ubiquitous yellow sodium line, but of the blue calcium line and the orange and green bands of lime, as well as of other lines which were not identified. The eudio­meter being at first clean and dry, the calcium must be derived either from the glass or from some spray of the water over which the gases with which the eudiometer was filled had been confined. It seemed incredible that the momentary flash should detach and light up lime from the glass, but subsequent observations have pointed to that con elusion. Our next experiments were made on the flash of the com­bining gases inclosed in an iron tube, half an inch in diameter and about 3 feet long, closed at one end with a plate of quartz, held in its place by a screw-cap and made tight by leaden washers. Two narrow brass tubes were brazed into the iron tube at right angles to the axis, one near each end, and one of these was connected with an air-pump, the other with the reservoir of gas. Into one of these brass tubes was cemented a piece of glass tube with a platinum wire fused into it whereby the electric spark was passed to fire the gas. The tube was placed so that its axis might be in line with the axis of the collimator of a spectroscope, and the flash observed as it travelled along the tube.

scholarly journals The Use of a Sheathless Basket via Miniature Ureteroscopes

1995 ◽  
Vol 1 (3) ◽  
pp. 177-181 ◽  
Author(s):  
Graham Watson
Keyword(s):  
Metallic Wire ◽  
The Wire ◽  
At Will ◽  
Wire Basket

The conventional use of a basket involves a metallic wire section that is contained within a polythene sheath. The wire basket can be withdrawn or protruded from the sheath using a handle. The advantage of this system is that the basket can be kept shut or open at will within the ureter. Thus one can keep the basket closed in order to maneuver the basket past a stone before opening it above the stone. With the development of efficient and safe lithotripsy modalities becoming widely available and with miniaturization of these and the ureteroscopes, it is becoming less common to dilate the ureter. Therefore it is not frequently possible to extract a stone intact. Baskets still can be used secondarily to extract the fragments. It is possible to use the basket wire without its sheath. The ureteroscope channel effectively becomes the sheath, and the basket opens immediately on protruding it beyond the ureteroscope. This has the following advantages: (a) A larger-diameter basket wire can be introduced. The very small baskets of 2F and 3F used via miniature ureteroscopes are very flimsy. When the sheath is removed, it becomes possible to use an otherwise 3F basket via a 2F channel. (b)The operator can work the basket usingjust two fingers close to the instrument channel port. This is more ergonomic than working an opening mechanism at the end of the basket, because this latter system takes the operator's hand away from the instrument. (c) The basket can be detached more readily from the ureteroscope, should it become, impacted together with a stone within the ureter. This makes it possible to reinsert the ureteroscope alongside the basket and fragment the stone within the basket, provided that there is no reinforced section to the inner wire at the handle.

scholarly journals XIII. Quadrant electrometers

1891 ◽  
Vol 182 ◽  
pp. 519-564
Keyword(s):  
External Action ◽  
The Other ◽  
Potential Difference ◽  
Platinum Wire ◽  
Anomalous Variation ◽  
Standard Formula ◽  
Modes Of Vibration ◽  
The Wire ◽  
Large Charge

In 1886, on continuously charging up the needle of Sir William Thomson’s bifilar quadrant electrometer, No. 5, made by Messrs. White, of Glasgow, and in use at the laboratories at the Central Institution, it was noticed that the deflection of the needle, when the same P. D. (potential difference) was maintained between the quadrants, instead of steadily increasing, first increased and then diminished, so that both for a large charge on the needle as well as for a small, the sensibility of the instrument was small. A similar effect had been described by Dr. J. Hopkinson in the Proceedings of the Physical Society,’ vol. 7, Part I., for the previous year, and the explanation he gives of this curious result is that if the aluminium needle be below the centre of the quadrants the downward attraction of the needle, which increases with the square of the needle’s charge, increases the pull on the bifilar suspension, and so for high charges more than compensates for the increased deflecting couple due to electrical action. On raising, however, the needle of our electrometer much above the centre of the quadrants, the anomalous variation of sensibility of the instrument, with increase of charge in the needle, did not disappear, and even when the needle was raised so that it was very close to the top of the quadrants, and when, if Dr. Hopkinson’s explanation were correct, the sensibility (or deflection correspond­ing with a given P. D. between the quadrants) ought to have been very great for a large charge on the needle, it was, on the contrary, found to be small. As the needle had been somewhat damaged while the instrument was in the possession of the late Mr. Cromwell Yarley, before it was so kindly made over to the Central Institution by his son, Mr. Cromwell Yarley, Junior, together with other apparatus belonging to his father, a new needle, platinum wire, and weight, were obtained from Messrs. White. On suspending the new needle with the fine platinum wire and weight, as received from Messrs. White, the needle was found to have two modes of vibration, one the ordinary slow one, when the platinum weight turned in the acid at the bottom of the Leyden jar, and the other a very quick one, due to the twisting of the wire itself without the weight moving. This quick vibration was removed by replacing the fine platinum wire supplied by Messrs. White with a somewhat thicker one. The quadrants were adjusted for symmetry, the silk fibres tightened so as to have equal tension, as shown by the sensibility for a given potential of the needle, being a minimum, and the electrometer again tried, but it was still found that when the quadrants were close to one another, and when, therefore, as the needle was best shielded from external action, the standard formula for the electrometer might be expected to be most nearly fulfilled, the sensibility as before, first increased as the charge in the needle was increased, and then steadily diminished for further increase of charge on the needle. It was now, however, observed that, if the distance separating the quadrants was increased to inch, the sensibility tended to a limit for a large charge instead of first increasing and then diminishing.

scholarly journals XIV.—On Torsional Oscillations of Wires

1900 ◽  
Vol 39 (2) ◽  
pp. 425-455
Author(s):  
W. Peddie
Keyword(s):  
Philosophical Magazine ◽  
Torsional Oscillations ◽  
Series Of Experiments ◽  
The Wire ◽  
The Difference ◽  
Image Position

This paper is in continuation of two others, on the same subject, previously communicated to the Society. In the First Paper (Philosophical Magazine, July 1894) it was shown that the formulawhere n, a, and b are constants in any one experiment, represents with accuracy the relation between y, the range of oscillation, and x, the number of oscillations which have taken place since torsion was first applied and the wire was left to itself, so that the oscillations gradually diminished. The apparatus employed, and the method of observation used, were identical with those described in the Second Paper above referred to. The wire which was experimented upon was the same as that used on the previous occasions. Its length, as given in the First and Second Papers, was 89·1 cm. A measurement made on the date 19.10.1897, in the course of the last series of experiments described in the present paper, showed that the length had become 89*3 cm. This increase was doubtless due to the fact that the heavy lead oscillator had been left attached to the wire during the whole of the intervening period. On the date given, it was also found that, with the same oscillator as was used in the experiments first described, ten oscillations were performed in 81 seconds, when the range was large, while 79 seconds were occupied when the range was small. This observation verified the result stated in the First Paper, that the period slightly increases as the range increases. It also showed that the wire was practically in the same condition as it was at first, in so far as elastic qualities are concerned; for the corresponding periods were only slightly less in earlier experiments, the difference being largely accounted for by the slight increase of length of the wire.

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