scholarly journals XIV. Experimental researches in electricity.—Tenth series

1835 ◽  
Vol 125 ◽  
pp. 263-274
Keyword(s):  
Electric Current ◽  
Royal Society ◽  
The Other ◽  
The One ◽  
Experimental Researches

1119. I have lately had occasion to examine the voltaic trough practically, with a view to improvements in its construction and use; and though I do not pretend that the results have anything like the importance which attaches to the discovery of a new law or principle, I still think they are valuable, and may therefore, if briefly told, and in connexion with former papers, be worthy the approbation of the Royal Society. 16. On an improved form of the Voltaic Battery . 1120. In a simple voltaic circuit (and the same is true of the battery) the chemical forces which, during their activity, give power to the instrument, are generally divided into two portions; the one of these is exerted locally, whilst the other is transferred round the circle (947. 996.); the latter constitutes the electric current of the instru­ment, whilst the former is altogether lost or wasted. The ratio of these two portions of power may be varied to a great extent by the influence of circumstances: thus, in a battery not closed, all the action is local; in one of the ordinary construction, much is in circulation when the extremities are in communication; and in the perfect one, which I have described (1001.), all the chemical power circulates and becomes elec­tricity. By referring to the quantity of zinc dissolved from the plates (865. 1126.), and the quantity of decomposition effected in the volta-electrometer (711. 1126.) or elsewhere, the proportions of the local and transferred actions under any particular circumstances can be ascertained, and the efficacy of the voltaic arrangement, or the waste of chemical power at its zinc plates, be accurately determined.

scholarly journals VII. Experimental researches in electricity.-Twenty-third Series

1850 ◽  
Vol 140 ◽  
pp. 171-188 ◽  
Keyword(s):  
Magnetic Field ◽  
Mode Of Action ◽  
Royal Society ◽  
The Other ◽  
Experimental Proof ◽  
Philosophical Paper ◽  
Iron Nickel ◽  
The One ◽  
Experimental Researches ◽  
The Magnetic Field

Four years ago I suggested that all the phenomena presented by diamagnetic bodies, when subjected to the forces in the magnetic field, might be accounted for by assuming that they then possessed a polarity the same in kind as, but the reverse in direction of, that acquired by iron, nickel and ordinary magnetic bodies under the same circumstances (2429. 2430.). This view was received so favourably by Plücker, Reich and others, and above all by W. Weber, that I had great hopes it would be confirmed; and though certain experiments of my own (2497.) did not increase that hope, still my desire and expectation were in that direction. Whether bismuth, copper, phosphorus, &c., when in the magnetic field, are polar or not, is however an exceedingly important question; and very essential and great differences, in the mode of action of these bodies under the one view or the other, must be conceived to exist. I found that in every endeavour to proceed by induction of experiment from that which is known in this department of science to the unknown, so much uncertainty, hesitation and discomfort arose from the unsettled state of my mind on this point, that I determined, if possible, to arrive at some experimental proof either one way or the other. This was the more needful, because of the conclusion in the affirmative to which Weber had come in his very philosophical paper; and so important do I think it for the progress of science, that, in those imperfectly developed regions of knowledge, which form its boundaries, our conclusions and deductions should not go far beyond, or at all events not aside from the results of experiment (except as suppositions), that I do not hesitate to lay my present labours, though they arrive at a negative result, before the Royal Society.

scholarly journals Description of a new barometer, recently fixed up in the apart­ments of the Royal Society; with remarks on the mode hitherto pursued at various periods, and an account of that which is now adopted, for correcting the observed height of the mercury in the society’s barometer

1843 ◽  
Vol 4 ◽  
pp. 1-3
Keyword(s):  
Royal Society ◽  
The Other ◽  
Chemical Effect ◽  
The Absolute ◽  
The One ◽  
And Control ◽  
Usual Scale

The barometer, here alluded to, may in some measure be consi­dered as two separate and independent barometers, inasmuch as it is formed of two distinct tubes dipping into one and the same cistern of mercury. One of these tubes is made of flint glass, and the other of crown glass, with a view to ascertain whether, at the end of any given period, the one may have had any greater chemical effect on the mercury than the other, and thus affected the results. A brass rod, to which the scale is attached, passes through the framework, between the two tubes, and is thus common to both : one end of which is furnished with a fine agate point, which, by means of a rack and pinion moving the whole rod, may be brought just to touch the surface of the mercury in the cistern, the slightest contact with which is immediately discernible; and the other end of which bears the usual scale of inches, tenths, &c.; and there is a separate vernier for each tube. A small thermometer, the bulb of which dips into the mercury in the cistern, is inserted at the bottom : and an eye­piece is also there fixed, so that the agate point can be viewed with more distinctness and accuracy. The whole instrument is made to turn round in azimuth, in order to verify the perpendicularity of the tubes and the scale. It is evident that there are many advantages attending this mode of construction, which are not to be found in the barometers as usu­ally formed for general use in this country. The absolute heights are more correctly and more satisfactorily determined ; and the per­manency of true action is more effectually noticed and secured. For, every part is under the inspection and control of the observer; and any derangement or imperfection in either of the tubes is imme­diately detected on comparison with the other. And, considering the care that has been taken in filling the tubes, and setting off the scale, it may justly be considered as a standard barometer . The pre­sent volume of the Philosophical Transactions will contain the first register of the observations that have been made with this instru­ment.

scholarly journals On some circumstances relating to the economy of bees

1833 ◽  
Vol 2 ◽  
pp. 346-347
Keyword(s):  
Royal Society ◽  
The State ◽  
The Other ◽  
Compact Mass ◽  
Whole Number ◽  
Permanent Settlement ◽  
The One ◽  
Hollow Tree ◽  
As If

The author had already stated, in a former communication to the Royal Society, his having noticed that for several days previous to the settling of a swarm of bees in the cavity of a hollow tree adapted to their reception, a considerable number of these insects were incessantly employed in examining the state of the tree, and particularly of every dead knot above the cavity which appeared likely to admit water. He has since had an opportunity of observing that the bees who performed this task of inspection, instead of being the same individuals as he had formerly supposed, were in fact a continual succession of different bees; the whole number in the course of three days being such as to warrant the inference that not a single labouring bee ever emigrates in a swarm without having seen its proposed future habitation. He finds that the same applies not only to the place of permanent settlement, but also to that where the bees rest temporarily, soon after swarming, in order to collect their numbers. The swarms, which were the subjects of Mr. Knight’s experiments, showed a remarkable disposition to unite under the same queen. On one occasion a swarm, which had arisen from one of his hives, settled upon a bush at a distance of about twenty-five yards; but instead of collecting together into a compact mass, as they usually do, they remained thinly dispersed for nearly half an hour; after which, as if tired of waiting, they singly, one after the other, and not in obedience to any signal, arose and returned home. The next morning a swarm issued from a neighbouring hive, and proceeded to the same bush upon which the other bees had settled on the preceding day; collecting themselves into a mass, as they usually do when their queen is present. In a few minutes afterwards a very large assemblage of bees rushed from the hive from which the former swarm had issued, and proceeded directly to the one which had just settled, and instantly united with them. The author is led from these and other facts to conclude that such unions of swarms are generally, if not always, the result of previous concert and arrangement.

XXIV.—On the Temperature Coefficient of Concentration Cells, in which the same salt is dissolved in two different solvents

1912 ◽  
Vol 31 ◽  
pp. 375-396
Author(s):  
A. P. Laurie
Keyword(s):  
Temperature Coefficient ◽  
Potassium Iodide ◽  
Royal Society ◽  
Platinum Electrode ◽  
The Other ◽  
Absolute Alcohol ◽  
Concentration Cell ◽  
New Type ◽  
The One ◽  
Concentration Cells

In a paper read before the Royal Society of Edinburgh (Proc. Roy. Soc. Edin., xxviii., part v., p. 382 (1908); Zeit. phys. Chem., lxiv. 5) I described a new type of concentration cell, in which the one platinum electrode was surrounded by a solution of ·025 molecules of KI containing ·001 molecules of iodine dissolved in absolute alcohol, and the other electrode was surrounded by ·025 molecules of KI and ·001 molecules of iodine, dissolved in water. This cell developed a considerable E.M.F. of ·198 volts at 25° C. in the direction which would transfer the iodine from water to alcohol and potassium iodide from alcohol to water.

scholarly journals On the magnetic power of soft iron

1837 ◽  
Vol 3 ◽  
pp. 187-188
Keyword(s):  
Electric Current ◽  
Copper Wire ◽  
Complete Removal ◽  
The Other ◽  
Present Communication ◽  
Hard Steel ◽  
Electric Current Passing ◽  
Good Contact ◽  
The One ◽  
Single Helix

When free magnetism is developed by induction, and is not retained in that state by what has been termed the coercive force of hard steel, it has generally been considered that all the phenomena due to the existence of free magnetism cease on the removal of the inducing cause. The object of the present communication is to show that such is not the fact. From a variety of experiments described by the author, it appears that soft iron continued to exhibit strongly the attraction due to the developement of magnetism long after the means by which the magnetism had been originally excited had ceased to act. In these experiments, bars of soft iron, in the form of a horseshoe, had a single helix of copper wire wound round them, so that on the ends of the wire being brought into contact with the poles of a voltaic battery, the iron became an electromagnet. With one of these horse-shoes, while the connexion between the ends of the helix and the poles of the battery existed, the soft iron, having a keeper applied to its poles, supported 125 pounds it supported 56 pounds after that connexion had been broken, and continued to retain the power of supporting the same weight after an interval of several days, care having been taken not to disturb, during the time, the contact between the horse-shoe and its keeper. On this contact, however, being broken, nearly the whole attractive power appeared to be immediately lost. The author describes several instances of the same kind, particularly one in which the contact between the ends of the horse-shoe of soft iron and its keeper having been undisturbed during fifteen weeks, the attractive power continued undiminished. Although the interposition of a substance, such as mica or paper, between the ends of the horse-shoe and its keeper necessarily diminished the force of attraction, it did not appear to diminish the power of retaining that force. In a case where the electromagnet of soft iron and its keeper were equal semi-circles, the author found, what may appear singular, that the arrangement of the magnetism during the time that the electric current traversed the helix, appeared not to be the same as after the cessation of that current; in the one case similar, and in the other dissimilar, poles being opposed to each other at the opposite extremities of the two semi-circles. Whether the magnetism was originally developed in the soft iron by means of an electric current passing round it, or by passing over its surface the poles of an electromagnet, or those of a common magnet of hard steel, it appeared to possess the same power of retaining a large portion of the magnetism thus developed. The retention of the magnetism does not appear to depend upon the relative positions of the ends of the horse-shoe and the keeper remaining undisturbed, but on their contact remaining unbroken: for one keeper was substituted for another without diminution of this power; care being taken that the second should be in good contact with both ends of the horse-shoe before the complete removal of the first.

scholarly journals VII.—On the Motion of a Heavy Body along the Circumference of a Circle

1865 ◽  
Vol 24 (1) ◽  
pp. 59-71
Author(s):  
Edward Sang
Keyword(s):  
Royal Society ◽  
Elliptic Functions ◽  
The Other ◽  
Philosophical Magazine ◽  
Circular Arc ◽  
Heavy Body ◽  
Great Ease ◽  
Fourth Volume ◽  
The Common ◽  
The One

In the year 1861 I laid before the Royal Society of Edinburgh a theorem concerning the time of descent in a circular arc, by help of which that time can be computed with great ease and rapidity. A concise statement of it is printed in the fourth volume of the Society's Proceedings at page 419.The theorem in question was arrived at by the comparison of two formulæ, the one being the common series and the other an expression given in the “Edinburgh Philosophical Magazine” for November 1828, by a writer under the signature J. W. L. Each of these series is reached by a long train of transformations, developments, and integrations, which require great familiarity with the most advanced branches of the infinitesimal calculus; yet the theorem which results from their comparison has an aspect of extreme simplicity, and seems as if surely it might be attained to by a much shorter and less rugged road. For that reason I did not, at the time, give an account of the manner in which it was arrived at, intending to seek out a better proof. On comparing it with what is known in the theory of elliptic functions, its resemblance to the beautiful theorem of Halle became obvious; but then the coefficients in Halle's formulæ are necessarily less than unit, whereas for this theorem they are required to be greater than unit.

X. An account of some experiments upon coloured shadows

1794 ◽  
Vol 84 ◽  
pp. 107-118 ◽  
Keyword(s):  
White Paper ◽  
The Other ◽  
Proper Position ◽  
Clear Sky ◽  
The North ◽  
Darkened Room ◽  
The One ◽  
Experimental Researches ◽  
To Receive ◽  
Opaque Body

Dear Sir, Since my last letter, being employed in the prosecution of my experiments upon light, I was struck with a very beautiful, and what to me appeared to be a new appearance. Desirous of comparing the intensity of the light of a clear sky, by day, with that of a common wax candle, I darkened my room, and letting the daylight from the north, coming through a hole near the top of the window-shutter, fall at an angle of about 70° upon a sheet of very fine white paper, I placed a burning wax candle in such a position that its rays fell upon the same paper, and as near as I could guess, in the line of reflection of the rays of daylight from without; when interposing a cylinder of wood, about half an inch in diameter, before the centre of the paper, and at the distance of about two inches from its surface, I was much surprised to find that the two shadows projected by the cylinder upon the paper, instead of being merely shades without colour, as I expected, the one of them, that which, corresponding with the beam of daylight, was illuminated by the candle, was yellow ; while the other, corresponding to the light of the candle, and consequently illuminated by the light of the heavens, was of the most beautiful blue that it is possible to imagine. This appearance, which was not only unexpected, but was really in itself in the highest degree striking and beautiful, I found, upon repeated trials, and after varying the experiment in every way I could think of, to be so perfectly permanent, that it is absolutely impossible to produce two shadows at the same time from the same body, the one answering to a beam of daylight, and the other to the light of a candle or lamp, without these shadows being coloured, the one yellow and the other blue . The experiment may very easily be made at any time by day, and almost in any place, and even by a person not in the least degree versed in experimental researches. Nothing more is necessary for that purpose than to take a burning candle into a darkened room in the day time, and open one of the window-shutters a little, about half or three quarters of an inch for instance; when the candle being placed upon a table or stand, or given to an assistant to hold, in such a situation that the rays from the candle may meet those of daylight from without, at an angle of about 40°, at the surface of a sheet of white paper, held in a proper position to receive them, any solid opaque body, a cylinder, or even a finger, held before the paper, at the distance of two or three inches, will project two shadows upon the paper, the one blue, and the other yellow.

scholarly journals Note on Dr. Burdon Sanderson’s latest views of ferments and germs

1878 ◽  
Vol 26 (179-184) ◽  
pp. 353-356
Keyword(s):  
High Temperature ◽  
Bacillus Anthracis ◽  
Royal Society ◽  
The Other ◽  
Spontaneous Generation ◽  
Outer Line ◽  
Living Things ◽  
Characteristic Behaviour ◽  
The Difference ◽  
The One

While writing the paper which the Council of the Royal Society has recently done me the honour of accepting for the Philosophical Transactions, the abstract of a lecture delivered by Dr. Burdon Sanderson to the association of Medical Officers of Health was placed in my hands. The teem in which the author’s name is justly held will certainly give eight and currency to the views enunciated in this lecture. Speaking: ferments Dr. Sanderson says :—“ In defining the nature of fermentition we are in a dilemma, out of which there is no escape except by compromise. A. ferment is not an organism, because it has no structure. It is not a chemical body, because when it acts upon other bodies it maintains its own molecular integrity. On the whole, it resembles an organism such more than it resembles a chemical body, for its characteristic behaviour is such as, if it had a structure, would prove it to be living. Ten years ago the opponents of spontaneous generation were called Pansperusts, because it was supposed that in the so-called generation equivoca, in very case in which Bacteria appeared to spring out of nothing, the result as referable to the influence of unseen but actually existing germs. The assearches of the last few years have carried us beyond this stage. . . . the outer line of defence, represented by the aphoristic expression omne ivum ex ovo , has been for some time abandoned. The ground which the orthodox biologist holds now, as against the heterodox, is not that every bacterium must have been born of another Bacterium, but that every Bacterium must have been born of something which emanated from another bacterium, that something not being assumed to be endowed with structure in the morphological or anatomical sense, but only in the molecular chemical sense. It is admitted by all, even by Professor Tyndall, that, far as structure is concerned, the germinal or life-producing matter out which Bacteria originate exhibits no characters which, can be appreciated by the microscope; and other researches have proved that the Seminal matter is capable of resisting destructive influences, particularly those of high temperature, which are absolutely fatal to the Bacteria themselves. Germs have given place to things which are ultramicr scopical—to molecular aggregates—of which all we can say is, what we have already said about the ferments, that they occupy the border between living and non-living things.” As directed against “ germs ” the argument that the “ germinal matter is capable of resisting destructive influences which are fatal to the themselves, will, I think, be found on consideration to lack validity Nobody is better acquainted than Dr. Sanderson with the two forms under which the contagium of splenic fever appears. He knows that the one fugitive and readily destroyed, the other persistent and destroyed will difficulty. Now the recent researches of Koch, which have been verified by Cohn, prove conclusively that the difference here referred to is bast upon the fact that the fugitive contagium is the developed organism Bacillus anthracis, while the persistent contagium is the spore of tin organism. Dallinger’s excellent observations also establish a difference between the death-temperatures of monad germs and of adult monads while I need not do more than refer to the forthcoming Part of till Philosophical Transactions for illustrations of the extraordinary differences of the same nature which my recent researches have brought to light.

scholarly journals Experimental researches in electricity: Twelfth series

1843 ◽  
Vol 4 ◽  
pp. 49-52
Keyword(s):  
Electric Discharge ◽  
Physical State ◽  
Charged Particles ◽  
Preceding Paper ◽  
The Other ◽  
Electric Conduction ◽  
The One ◽  
Experimental Researches ◽  
Inductive Charge ◽  
Perfect Conduction

The object of the present series of researches is to examine how far the principal general facts in electricity are explicable on the theory adopted by the author, and detailed in his last memoir, re­lative to the nature of inductive action. The operation of a body charged with electricity, of either the positive or negative kind, on other bodies in its vicinity, as long as it retains the whole of its charge, may be regarded as simple induction , in contradistinction to the effects which follow the destruction of this statical equilibrium, and imply a transit of the electrical forces from the charged body to those at a distance, and which comprehend the phenomena of the electric discharge . Having considered, in the preceding paper, the process by which the former condition is established, and which consists in the successive polarization of series of contiguous particles of the interposed insulating dielectric; the author here proceeds to trace the process, which, taking place consequently on simple induction, terminates in that sudden, and often violent interchange of electric forces constituting disruption , or the electric discharge. He investigates, by the application of his theory, the gradual steps of transition which may be traced between perfect insulation on the one hand, and perfect conduction on the other, derived from the varied degrees of specific electric relations subsisting among the particular substances interposed in the circuit: and from this train of reasoning he deduces the conclusion that induction and conduction not only depend essentially on the same principles, but that they may be regarded as being of the same nature, and as differing merely in degree. The fact ascertained by Professor Wheatstone, that electric conduction, even in the most perfect conductors, as the metals, requires for its completion a certain appreciable time, is adduced in corrobo­ration of these views; for any retardation, however small, in the transmission of electric forces can result only from induction; the degree of retardation, and, of course, the time employed, being proportional to the capacity of the particles of the conducting body for retaining a given intensity of inductive charge. The more perfect insulators, as lac, glass and sulphur, are capable of retaining electri­city of high intensity; while, on the contrary, the metals and other excellent conductors, possess no power of retention when the in­tensity of the charge exceeds the lowest degrees. It would appear, however, that gases possess a power of perfect insulation, and that the effects generally referred to their capacity of conduction, are only the results of the carrying power of the charged particles either of the gas, or of minute particles of dust which may be present in them: and they perhaps owe their character of perfect insulators to their peculiar physical state, and to the condition of separation under which their particles are placed. The changes produced by heat on the conducting power of different bodies is not uniform; for in some, as sulphuret of silver and fluoride of lead, it is increased; while in others, as in the metals and the gases, it is diminished by an augmentation of temperature.

III. On the causes of the great variation among the different measures of the Earth’s mean density

1857 ◽  
Vol 8 ◽  
pp. 295-299 ◽  
Keyword(s):  
Royal Society ◽  
The Other ◽  
The One ◽  
Limits Of Error

The result of the Pendulum experiments in the Harton Colliery, undertaken by the Astronomer Royal in 1854, and detailed in his paper presented to the Royal Society in January 1856, appears at first sight rather startling, as adding to the already somewhat discrepant measures or estimates of the earth’s mean density one more discordant than ever ; so that we have now values ranging from 4.7 to nearly 6.6; a range, which, in the absence of any sufficient ground for selecting any one as true to the exclusion of the rest, would seem to deprive us of all confidence in their correctness as measures , and leave them rather to be classed as estimates of a very rough description. But it will be my endeavour to show, that, while none of the methods employed are capable of giving strictly accurate results, the Cavendish experiment is the one which may be relied on as giving a good approximation to the truth, within limits of error (when conducted with proper precaution) far less than those to which either of the other methods are liable.

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