358 



NATURE 



{Feb. 7, 1889 



this as an explanation of the fact that normally the flow of the 

 lymph from the thoracic duct into the blood produces no poisonous 

 effect. 



(2) It has long been known that mere mechanical disturbance 

 to the circulation, unless it be of a most extreme character, will 

 not produce dropsy. The ligature of the femoral vein in the 

 dog produces no dropsy. But if previous to the ligature, some 

 of the lymph fluid or fibrinogen solution be injected into the 

 blood, the most severe oedema of the leg is produced, or this 

 accompanied by haemorrhage. 



(3) In cardiac disease and disturbance of the circulation 

 through the lungs there is no reason to suppose that a sudden 

 increase in the flow of lymph ever takes place. But it is certain 

 that the circulation of the blood in the neighbourhood of the 

 thoracic duct is materially slowed in these conditions. This 

 slowing of the circulation acts in the same way as a more 

 rapid injection of lymph, and hence in cardiac disease the con- 

 ditions for fibrinogen intoxication — auto-infection from the lymph 

 — prevail. 



(4) The dropsy, which is so common a symptom of cardiac 

 disease, is commonly explained as being due to the mechanical 

 disturbance of the circulation. This explanation does not 

 harmonize with experimental observations. The fact that even 

 very slight fibrinogen intoxication produces a pronounced 

 tendency to dropsy renders it extremely probable that the 

 dropsy and other symptoms of cardiac disease depend on 

 fibrinogen intoxication. 



Physical Society, January 26.— Prof. Fuller, F.R.S., in 

 the chair. — The thanks of the Society were tendered to Mr. 

 Freeman, for presenting to the library a rare and interesting 

 work, " Reflexions sur la Puissance Motrice du Feu, et surles 

 Machines propres a developper cette Puissance," par S. Carnot, 

 ancien eleve de I'Ecole Polytechnique. — Dr. S. P. Thompson 

 read three notes on polarized light, entitled respectively : " The 

 Structure of Natural Diffraction Gratings of Quartz," " Ahrens's 

 Modification of Delezenne's Polarizer," and "The Use of 

 Two Quarter-Wave Plates in Combination with a Stationary 

 Polarizer. " Two microscope slides of iridiscent quartz (prepared 

 by the_ late Mr. Darker), which have recently come into the 

 possession of the author, exhibit remarkable peculiarities. 

 Both act like diffraction gratings, one as if the rulings were 

 about 12,000, and the other about 26,000, to the inch. On 

 examining the specimens by the microscope, it was found that 

 the parts which exhibited the grating effect showed a spindle-like 

 structure, and by micrometer measurements the dimensions of 

 the spindle-shaped bodies were determined to be from i/iooo to 

 1/3000 of an inch in diameter, and i/ioo to 1/300 of an inch long. 

 These were much too large to cause the effects noticed, but on 

 closer examination it was found that the bodies were crossed at 

 right angles by fine markings, the distances between which are in 

 close accordance with those deduced from the spectra produced. 

 As a probable cause of the phenomenon, the author mentioned 

 a recent paper by Prof. Judd, " On the Production of a Lamellai 

 Structure in Quartz by Pressure," and suggested the possibility of 

 making diffraction gratings by such means. Ahrens's modifica- 

 tion of Delezenne's polarizer consists of a total- reflection prism 

 combined with glass plates and black glass mirror, arranged so 

 that the polarized beam is parallel to the original one. The 

 combination of plates and mirror is adopted so as to give enough 

 light and still keep the polarization sufficiently good. One or 

 two plates laid over the mirror are found to give the best results 

 The fact that a beam polarized by reflection is not coinciden 

 with the original beam, renders it inconvenient, if not impossible 

 to rotate the polarizer, and to ove rcome this defect, the author 

 has arranged two quarter-wave plates, one of which may be 

 rotated. The first plate circularly polarizes the plane-polarized 

 beam, and the second (or rotating one) re-plane-polarizes it in 

 any desired plane. Objects were shown on the screen to 

 illustrate the degree of perfection attainable by using the new 

 polarizer in combination with the two quarter-wave plates. — A 

 note on a relation between magnetization and speed in a dynamo 

 machine vfas read by the same author. In a note presented to 

 the Society in June last, it was shown that 2p . 2R = 4ir«CS ; 

 where So, and 2R are the magnetic and electric resistances re- 

 spectively, n = speed, and C and S the numbers of armature 

 and field windings. By writing the equation in the form — 

 47rCS _ 2p 

 5R ~ « ' 

 it is seen that, when the electric resistance is maintained constant, 

 the magnetic resistance is proportional to speed. — Prof. Herroun 



read selections from a paper on the divergence of electromotive 

 forces from thermo-chemical data. The fact that the electro- ' 

 motive forces of voltaic cells do not always coincide with 

 calculated values has not hitherto received a satisfactory 

 explanation, and this paper describes an experimental re.-earch 

 bearing on the question. Several suggested explanations are 

 given. In some cells the anticipated chemical change does 

 not occur, and some metals become coated with oxide or sub- 

 salts ; others are affected, by dissolved gases, and the hydration 

 or solution of the salts formed may supplement or diminish the 

 E.M.F. of a cell, as well as the absorption or evolution of 

 sensible heat. The question of absorption and evolution of heat 

 is the one chiefly dealt with. If such actions do take place, the 

 total heat evolved by passing a definite current through the cell 

 must depend on the direction of the current, and by inclosing 

 the cell in a calorimeter the difference should be detected. The 

 total heat developed by a current C in ^ seconds is— 



Qh-t y eQ.t 



7. ' 

 where r is the resistance of the cell, and c the divergence of the 

 observed from the calculated E.M.F., the - or -f sign de- 

 pending on the direction of the current. In the case of mercury 

 cells, which are usually said to give about half a volt excess 

 E.M.F. , the heat was found to be independent of the direction 

 of the current. The heats of formation of mercury salts were 

 then re-investigated, and the results showed that Julius Thomsen's 

 numbers (the ones usually accepted) were greatly in excess o 

 the true values. This accounts for the difference between the 

 observed E.M.F. 'sand those calculated from Thomsen's numbers. 

 A copper, silver, nitrate cell was tested in the calorimeter, and 

 the reversible heal effect agreed closely with that deduced from 

 the " thermo-voltaic constant," or divergence of observed from 

 calculated E.M.F. Other experiments on tin, lead, nickel, 

 iron, and calcium cells are described, and the chief conclusions 

 arrived at are : (i) the primary factor in determing the E.M.F. 

 of a voltaic cell is the relative heat of formation of the anhydrous 

 salts of the two metals employed ; (2) that this li.M.F. may set 

 up chemical changes of a different direction and character from 

 those predicable from the heat of formation of the dissolved 

 salts ; (3) that the E.M.F. set up by (i) may be, and usually is, 

 supplemented by the energy due to the hydration or solution of 

 the solid salts, and may have values which accord with the heat 

 of formation of the dissolved salts. The absorption or evolution 

 of sensible heat depends primarily on the attraction between 

 the salts and water, combined with the heat of solution. Finally, 

 the author states that the E.M.F. of a cell gives a more accurate 

 measurement of chemical affinity than that derived from calori- 

 metric observations. 



Chemical Society, January 17.— Mr. W. Crookes, F.R.S., 

 in the chair. — The following papers were read : — A cubical 

 form of bismuthous oxide, by Messrs. M. M. P. Muir and A. 

 Hutchinson. When the puce-coloured precipitate produced by 

 adding an excess of potassium cyanide to a boiling solution of 

 bismuth nitrate in dilute nitric acid is repeatedly treated with 

 boiling concentrated potash solution, a residue is left, consisting 

 of tetrahedral crystals of bismuthous oxide, which have a density 

 of 8"838. — Cupric iodide, and the interaction of iodides with 

 cupric salts, by Mr. D. J. Carnegie. By digesting cuprous iodide 

 with iodine and water in a tightly closed bottle at 80° for a few- 

 minutes, the author has obtained solutions of cupric iodide con- 

 taining as much as o"82 gramme per 100 cubic centimetres, but 

 has been unable to obtain cupric iodide in the solid state, either 

 from such solutions or by other means. A well defined basic 

 periodide, Culg, aCuO, 4H2O, was obtained by digesting copper 

 with barium iodide. — Periodates, part 2, by Mr. C. W. Kimmins. 

 The periodates of lead, iron, copper, nickel, cadmium, and 

 silver were described. — Compounds of arsenious oxide with sul- 

 phuric anhydride, by Mr. R. H. Adie. A series of compounds, 

 of the formula As.^jOj . .rSOg, where x = i, 2, 4, or 8, can be 

 prepared by the interaction of arsenious oxide and either sul- 

 phuric acid or sulphuric anhydride. — A compound of boric acid 

 with sulphuric anhydride, by Mr. R. F. d'Arcy.— Notes of ex- 

 periments with butter fat, by Messrs. A. W. Blyth and G. H. 

 Robertson. The main result of the experiments is to show- 

 that butter fat is composed of about 54-5 per cent, of solid crys- 

 talline fats, and about 45 "5 per cent, of an oil. The authors 

 consider that butter is mainly made up of compound and not 

 simple triglycerides, and have sejjarated a crystalline glyceride,. 



to which they ascribe the formula (C,H,0.,) . C3H5 j ^''S^^S". 



