scholarly journals XIII. On the laws of polarisation and double refraction in regularly crystallized bodies. By David Brewster, LL. D. F. R. S. Lond. and Edin. In a letter to the Right Hon. Sir Joseph Banks, Bart. G. C. B. P. R. S

1818 ◽  
Vol 108 ◽  
pp. 199-273 ◽  
Keyword(s):  
Present State ◽  
General Principle ◽  
Royal Society ◽  
Physical Science ◽  
Double Refraction ◽  
General Law ◽  
Relative Value ◽  
Combined Action ◽  
The Subject ◽  
The Right

Dear sir, In the different memoirs which you have done me the honour of submitting to the Royal Society, I have considered principally those branches of the polarisation of light which relate to the superficial action, or the superinduced properties of uncrystallized bodies. In the course of these enquiries, my attention was frequently directed to the phenomena of regular crystals; but from the difficulty of procuring proper specimens, and the extreme perplexity of the subject, it was not till lately that I succeeded in reducing under a general principle all the complex appearances which result from the combined action of more than one axis of double refraction. Before I proceed to trace the steps which have conducted me to this general law, I must entreat the indulgence of the Society, while I attempt to give a brief and rapid view of the present state of our knowledge respecting the laws of double refraction. They will thus be able to appreciate more correctly the relative value of those successive generalisations by which this subject has been raised to one of the most interesting departments of physical science.

On the laws of polarization and double refraction in regularly crystal­lized bodies. By David Brewster, LL. D. F. R. S. and Edin. In a letter to the Right Hon. Sir Joseph Banks, Bart. G. C. B. P. R. S

1833 ◽  
Vol 2 ◽  
pp. 92-93
Keyword(s):  
Optical Properties ◽  
General Principle ◽  
General View ◽  
Double Refraction ◽  
Primitive Form ◽  
General Law ◽  
Combined Action ◽  
The Right ◽  
Polarization Of Light ◽  
High Degree

In the different inquiries which the author has already laid before this Society, his attention was often directed to the phenomena of regular crystals; but he only lately succeeded in reducing under a general principle all those complex appearances which result from the combined action of more than one axis of double refraction. In this paper Dr. Brewster gives a general view of the present state of our knowledge respecting the double refraction and polarization of light, and afterwards traces the steps which led him to the discovery of the general law. He began his researches by the examination of 165 crystals, in 145 of which he discovered the property of double refraction. In 80 he was able to ascertain whether they had one or more axes; and by examining the tints which they exhibited at va­rious angular distances from the axes, whence the forces emanate, he has been led to a general principle, which embraces all the phenomena and extends to the most complex as well as to the most simple de­velopment of the polarizing forces. This general principle, says Dr. Brewster, is in no respect an empyrical expression of the facts which it represents, nor is it supported by any empyrical data. Founded on the principles of mechanics, it is a law rigorously physical, by which we are enabled to calculate all the tints of the coloured rings, and all the phenomena of double refraction, with as much accuracy as we can compute the motions of the heavenly bodies. The faculty of depolarization, explained by the author in a former paper, has been considered as sufficient indication of two separate images; and upon this principle it has been stated that all crystals are doubly refractive whose primitive form is neither the cube nor the regular octohedron: but this is incorrect; for some of these crystals possess a doubly refracting structure in a high degree. Ad­mitting the statement, however, it could not have been used as a rule for determining whether a crystal refracts doubly or singly; for it is more difficult to detect the primitive form than to examine the optical properties. Tungstate of lime, for instance, would have been reckoned a crystal without double refraction, when Haüy believed its primitive form to be the cube, although it is highly doubly refractive.

XXIII. On the water-barometer erected in the hall of the Royal Society

1832 ◽  
Vol 122 ◽  
pp. 539-574 ◽  
Keyword(s):  
Royal Society ◽  
Physical Science ◽  
The Other ◽  
Metallic Tube ◽  
French Academy ◽  
History Of ◽  
The Subject ◽  
The Common ◽  
Academy Of Sciences ◽  
Made In

I have for some time entertained an opinion, in common with some others who have turned their attention tot he subject, that a good series of observations with a Water-Barometer, accurately constructed, might throw some light upon several important points of physical science: amongst others, upon the tides of the atmosphere; the horary oscillations of the counterpoising column; the ascending and descending rate of its greater oscillations; and the tension of vapour at different atmospheric temperatures. I have sought in vain in various scientific works, and in the Transactions of Philosophical Societies, for the record of any such observations, or for a description of an instrument calculated to afford the required information with anything approaching to precision. In the first volume of the History of the French Academy of Sciences, a cursory reference is made, in the following words, to some experiments of M. Mariotte upon the subject, of which no particulars appear to have been preserved. “Le même M. Mariotte fit aussi à l’observatoire des experiences sur le baromètre ordinaire à mercure comparé au baromètre à eau. Dans l’un le mercure s’eléva à 28 polices, et dans Fautre l’eau fut a 31 pieds Cequi donne le rapport du mercure à l’eau de 13½ à 1.” Histoire de I'Acadérmie, tom. i. p. 234. It also appears that Otto Guricke constructed a philosophical toy for the amusement of himself and friends, upon the principle of the water-barometer; but the column of water probably in this, as in all the other instances which I have met with, was raised by the imperfect rarefaction of the air in the tube above it, or by filling with water a metallic tube, of sufficient length, cemented to a glass one at its upper extremity, and fitted with a stop-cock at each end; so that when full the upper one might be closed and the lower opened, when the water would fall till it afforded an equipoise to the pressure of the atmo­sphere. The imperfections of such an instrument, it is quite clear, would render it totally unfit for the delicate investigations required in the present state of science; as, to render the observations of any value, it is absolutely necessary that the water should be thoroughly purged of air, by boiling, and its insinuation or reabsorption effectually guarded against. I was convinced that the only chance of securing these two necessary ends, was to form the whole length of tube of one piece of glass, and to boil the water in it, as is done with mercury in the common barometer. The practical difficulties which opposed themselves to such a construction long appeared to me insurmount­able; but I at length contrived a plan for the purpose, which, having been honoured with the approval of the late Meteorological Committee of this Society, was ordered to be carried into execution by the President and Council.

XIX. On the immediate principles of human excrements in the healthy state

1857 ◽  
Vol 147 ◽  
pp. 403-413 ◽  
Keyword(s):  
Royal Society ◽  
Physical Science ◽  
Alcoholic Solution ◽  
Healthy State ◽  
The Subject

In June 1854 I had the honour of communicating to the Royal Society an account of some investigations I had undertaken respecting the composition of the excrements of man and animals; since that time I have continued my researches on human excrements, and obtained further results which form the subject of the present paper. I have been most ably seconded in this work by my assistant, Mr. Frederick Dupré, Ph. D., and have derived much valuable aid from his thorough knowledge of chemical and physical science. The method of investigation employed in this instance is similar to that which had been adopted on the former occasion; alcohol and ether were again the principal means employed for conducting the analysis, chemical decompositions being thereby avoided and the constituents of excrements consequently obtained under the form of Immediate Principles . It will also be observed that in this case, for the purpose of extracting excretine, the alcoholic solution of excrements was in many instances not mixed with milk of lime, which simplified materially the operations and increased the interest of the investigation.

scholarly journals IX. On some hitherto undescribed optical properties of doubly refracting crystals.—Preliminary notice

1878 ◽  
Vol 26 (179-184) ◽  
pp. 384-386 ◽  
Keyword(s):  
Royal Society ◽  
Focal Point ◽  
The Body ◽  
Index Of Refraction ◽  
Double Refraction ◽  
Other Substances ◽  
The Subject ◽  
Microscopical Society ◽  
Royal Microscopical Society

In the Proceedings of the Royal Society (vol. xxiv. p. 393) Dr Royston-Pigott described a new refractometer to determine the index of refraction of liquids and other substances by means of the displacement of the focal point of an object seen through them with a low magnifying-power. Another paper on the subject was communicated by him to the Royal Microscopical Society, and subsequently published its Journal. After the reading of this paper I said that it appeared me probable that the same principle might be applied with advantage the determination of the index of refraction of minerals. The chief question was how to make the requisite measurements by means of such a addition to an ordinary microscope as would not in any way interfere with its general use for other purposes. This I accomplished by fixing graduated scale to the body of the microscope and a vernier to the supporting arm, so that the position of the focal point can be read off to within about 1/2000 of an inch. I described this arrangement and pointed out its value in connexion with mineralogy at a meeting of the Mineralogical Society last March, and an account of it was published in the Journal of the Society. I have since learned that a very similar addition was made to a microscope in Professor Clifton’s laboratory at Oxford some eight years ago, and used for the measurement of the index of refraction of glass, but no account of it was ever published. When I came to study the index of refraction of doubly refracting minerals I was very soon struck with the fact that, instead of seeing at one focus the two systems of lines at right angles to each other, they were sometimes quite invisible, or one set was seen at one focus, and the whether at a very different, as though they had been ruled on the two opposite sides of a piece of glass. These curious phenomena were exhibited at the soirée of the Royal Society on the 25th of April last, and Processor Stokes immediately examined the question theoretically, and found that they could be explained by, and might have been predicted from, the known laws of double refraction, though apparently no one had ever studied them, either theoretically or practically. We therefore decided to investigate the problem independently. I was to make the practical observations, and he to give the theoretical explanations, the results being kept separate, but communicated conjointly to the Royal Society.

The Natural History of Whales

Polar Record ◽  
1942 ◽  
Vol 3 (24) ◽  
pp. 553-563
Author(s):  
N. A. Mackintosh
Keyword(s):  
Natural History ◽  
Southern Hemisphere ◽  
Present State ◽  
Comparative Anatomy ◽  
Sperm Whale ◽  
Anatomy And Physiology ◽  
Right Whales ◽  
History Of ◽  
The Subject ◽  
The Right

The purpose of this article is to give a general indication of the present state of our knowledge of whales, regarded as an element of the oceanic fauna, and to indicate some of the more important problems which still await solution. The term “whales” is used here to include only the largest of the Cetacea, which are the Right whales, the Rorquals and the Sperm whale; and the subject has to do with these whales in the collective sense, that is to say their habits as a community, and their breeding, growth and distribution, especially in the southern hemisphere, rather than with such matters as comparative anatomy and physiology.

scholarly journals III. Experiments on the depolarisation of light as exhibited by various mineral, animal, and vegetable bodies, with a reference of the phenomena to the general principles of polarisation. By David Brewster, LL. D. F. R. S. Edin and F. S. A. Edin. In a letter addressed to the Right Hon. Sir Joseph Banks, Bart. K. B. P. R. S

1815 ◽  
Vol 105 ◽  
pp. 29-53 ◽  
Keyword(s):  
Optical Properties ◽  
General Principle ◽  
Gum Arabic ◽  
Natural Philosopher ◽  
Double Refraction ◽  
Short Account ◽  
Vegetable Products ◽  
Direct Experiment ◽  
The Right ◽  
Iceland Spar

Dear Sir Towards the end of the year 1812, when I was engaged in examining the light transmitted through diaphanous bodies, I discovered the property which many of them possessed of depolarising the rays of light, or of depriving them of the po­larity which they had received, either by reflection from the surface of a transparent body, or by transmission through a plate of agate. A short account of these experiments, which were exhibited to many of my friends in Edinburgh, was soon afterwards published in my treatise on new philosophical instruments. As this singular property was possessed by numerous sub­stances that exhibited no marks of double refraction, and even by animal and vegetable products, such as horn, tortoise­ shell, and gum Arabic, it appeared necessary to distinguish it by a new name, and to refer it to a species of crystalliza­tion different from that of doubly refracting crystals. The circumstance, however, of agate and Iceland spar possessing the faculty both of polarising and depolarising light, and the constant relation in the position of the axes which regulated these apparently opposite actions, induced me to think that the two classes of phenomena had the same origin. This opinion was afterwards strengthened by an experiment with a bundle of glass plates, in which light was depolarised by polarising it in a new plane; but in applying the principle to other phenomena, I was baffled in every attempt to generalise them. By extending, however, and varying the experiments; by examining the optical properties of every substance which I could command, and by comparing their structure with the phenomena which they exhibited, I have been led to the general principle to which they all belong, and to a series of results which, from their very nature, could not easily have been established by direct experiment. These conclusions, independently of their optical consequences, are peculiarly in­teresting to the chemist and the natural philosopher, by dis­closing the structure of organised substances, and exhibiting new relations among the bodies of the animal, the vegetable, and the mineral kingdoms.

XIII. Experimental researches in voltaic electricity and electro-magnetism

1832 ◽  
Vol 122 ◽  
pp. 279-298 ◽  
Keyword(s):  
Experimental Investigation ◽  
Royal Society ◽  
Physical Science ◽  
The Subject ◽  
Experimental Researches ◽  
Made In

The splendid discoveries which have lately been made in magnetism and electro-magnetism have so much engaged the attention of philosophers, that the theory and laws of action of voltaic electricity, no longer possessing the charms of novelty, have been entirely neglected. The subject appearing to me full of interest, and lying at the very foundation of a large portion of physical science, induced me to undertake an experimental investigation of some of the most important points connected with it, the result of which I have the honour of laying before the Royal Society.

scholarly journals XXVIII. Some further observations on a new detonating substance. In a letter from Sir Humphry Davy, LL.D . F. R. S. V. P. R. I. to the Right Hon. Sir Joseph Banks, Bart. K .B. P. R. S

1813 ◽  
Vol 103 ◽  
pp. 242-251 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Royal Society ◽  
Compound I ◽  
The Subject ◽  
Humphry Davy ◽  
The Right

I have already described, in a letter which you were so good as to communicate to the Royal Society, a few facts respecting a new detonating compound. I shall now do myself the honour of mentioning to you some other particulars on the subject. I received, in April, a duplicate of the letter in which the discovery was announced, containing an Appendix, in which the method of preparing it was described. M. Ampere, my correspondent, states that the author obtained it by passing a mixture of azote and chlorine through aqueous solutions of sulphate, or muriate of ammonia. It is obvious, from this statement, that the substance discovered in France, is the same as that which occasioned my accident. The azote cannot be necessary; for the result is obtained by the exposure of pure chlorine to any common ammoniacal salt.

scholarly journals XXXIII. Remarks on Dr. Job Baster's observationes de corallinis, &c. printed above, p. 258. In a letter to the Right Honourable George Earl of Macclesfield, President of the R. S. from Mr. John Ellis, F. R. S

1757 ◽  
Vol 50 ◽  
pp. 280-287
Keyword(s):  
Royal Society ◽  
The Subject ◽  
The Right

My Lord, I Have read Dr. Job Baster's letter to the Royal Society; wherein he endeavours to prove, that corallines are not of an animal, but a vegetable nature; and has brought many arguments to support his system; which, to gentlemen not well acquainted with the subject, may appear plausible.

scholarly journals XXXIII. On the figure of the earth

1826 ◽  
Vol 116 ◽  
pp. 548-578 ◽  
Keyword(s):  
Present State ◽  
Royal Society ◽  
Mathematical Theory ◽  
Second Order ◽  
The Earth ◽  
First Approximation ◽  
Figure Of The Earth ◽  
The Subject ◽  
The Difference

The ellipticity of the earth, deduced by Captain Sabine from a series of pendulum experiments the most extensive, and apparently the most deserving of confidence, that has ever been made, differs considerably from that which, as is generally believed, is indicated by geodetic measures. The difference can only be explained by errors of observation, by peculiarities of local circumstances, or by some defect in the theory which connects the figure of the earth with the variation of gravity on its surface: under the last head may be placed defects in the mathematical part of the theory, and errors in the assumptions of the original constitution and present state of the earth. It was with a view to ascertain the sufficiency of the mathematical theory, that I undertook the investigations contained in this paper. The celebrated proposition called Clairaut's theorem, by which the earth's ellipticity is inferred from the variation of gravity on its surface, is obtained only by the rejection of the squares and higher powers of the ellipticity. It is by the same rejection that the figure of the earth, supposed a heterogeneous fluid, is proved to be an elliptic spheroid. It appeared therefore probable, that a more accurate theory might introduce some modification into Clairaut's theorem, and might also show he figure of the earth to differ from an ellipsoid ; and there was no reason to think that the first approximation to that figure was more accurate, than the first approximation to the motion of the moon’s perigee. The result of my investigation does not at all serve to reconcile the pendulum observations made by Captain Sabine with the measures of degrees : and with respect to one object, which I hoped to obtain, I am therefore completely unsuccessful. The theory shows, however, that the earth’s figure, on the usual suppositions as to its constitution, is not an elliptic spheroid; and the formulæ which I have obtained will give the means of determining very exactly the figure of the earth, when the experiments on the variation of gravity, or the measures of arcs on the earth’s surface, shall be thought sufficiently accurate. As the subject is one whose interest is not confined to the present time, I have ventured to offer my investigations to the Royal Society. The first part of the following sheets contains the theory of the heterogeneous earth, pushed so far as to include all the terms of the second order: it is succeeded by a comparison of this theory with Captain Sabine’s results, and with the best arcs of the meridian that have been measured and in the conclusion, I have offered some suggestions on the propriety of repeating some of these measures.

Sign in / Sign up

Export Citation Format

Share Document