increase in the force of the beat, at least in the ventricles (fig. 4). (2.) On the other hand the relation of the ventricular power to the arterial resistance may be such that the left ventricle is not able to expel its contents at each beat in the normal fashion. The recording lever fails to descend to the usual level between the contractions; it remains elevated to a considerable extent from the ordinary base line. The results occurring in both the conditions referred to-(1) and (2)—are not obviated by section of all the visible branches of the annulus of Vienssens, and of the vago-sympathetic in the neck and thorax. They appear to depend on properties of the heart itself, and not on the influence of extra-cardiac nerves. DESCRIPTION OF FIGURES. FIG. 1.-Tracing of auricles and ventricles, showing effects of clamping descending aorta (Ao.). In the ventricular tracing the upward movement indicates contraction; in the auricular tracing the downward movement indicates contraction. The time tracing shows half seconds. FIG. 2.-Tracing of auricles. Downward movement indicates contraction. Descending aorta clamped at the point marked ↓, and released at ↑. Time marker indicates half seconds. FIG. 3.-Tracing of auricles and ventricles. In the ventricular tracing contraction is represented by the upward movement, in the auricular tracing by the downward movement. Time marker shows half seconds. Clamping of descending aorta. FIG. 4.-Tracing of ventricles; upward movement indicates contraction. Increase in size of beats during the closure of the descending aorta. Time marker indicates half seconds. FIG. 5.-Tracings of auricles, ventricles and blood-pressure in left carotid artery. The lowest tracing marks the time in half seconds. The level of the ventricular tracing rises during closure of the descending aorta; there is incomplete emptying of the left ventricle at each systole. Transactions. Presents, June 7, 1888. Geneva :-Société de Physique et d'Histoire Naturelle. Mémoires. London :-Anthropological Institute. Journal. 8vo. London 1888. Vol. XVII. No. 4. East India Association. Journal. Vol. XX. No. 2. 8vo. 8vo. London 1888. The Association. Institution of Civil Engineers. Minutes of Proceedings. Vol. The Institution. XCII. 8vo. London 1888. The Society. Royal United Service Institution. Journal. Vol. XXXII. No. Victoria Institute. Journal of Transactions. Vol. XXI. No. 84. Mexico :- -Sociedad Científica "Antonio Alzate." Tomo 1. Núm. 9. 8vo. México 1888. The Institute. Memorias. The Society. Transactions (continued). Milan:-Reale Istituto Lombardo di Scienze e Lettere. Rendiconti. Ser. 2. Vols. XVIII-XIX. 8vo. Milano 1885-86; Memorie (Classe di Lettere e Scienze Storiche e Morali). Vol. XVI. Fasc. 3. 4to. Milano 1886. Ditto (Classe di Scienze Matematiche e Naturali). Vol. XV. Fasc. 4. Vol. XVI. Fasc. 1. 4to. Milano 1885-86. The Institute. Società Italiana di Scienze Naturali. Atti. Vol. XXIX. Fasc. 1-4. 8vo. Milano 1886. The Society. Naples :-Società Italiana delle Scienze. Memorie di Matematica e di Fisica. Ser. 3. Tomo VI. 4to. Napoli 1887. The Society. Foote (R. B.) Notes on some recent Neolithic and Paleolithic S.A. le Prince Albert de Monaco. Hinde (G. J.) On the History and Characters of the Genus Septastræa, d'Orbigny (1849), and the identity of its type species with that of Glyphastræa, Duncan (1887). 8vo. [London] 1888; Note on the spicules described by Billings in connexion with the Structure of Archæocyathus Minganensis. 8vo. Hertford 1888. The Author. Proctor (R. A.) Old and New Astronomy. Parts 1-3. London 1888. Messrs. Longman & Co. Rambaut (A. A.) The Total Lunar Eclipse of 1888, January 28, observed at the Dunsink Observatory. 8vo. London 1888; with two other excerpts in 8vo. The Author. Robertson (F. A.) The Customary Law of the Rawalpindi District. Vol. VI. 8vo. Lahore 1887. Record Department, India Office. Rokeby (T.) The Diary of Mr. Justice Rokeby. 4to. [London 1888.] [Privately printed.] Sir H. Peek, Bart. Spencer (J. W.) Glacial-Erosion in Norway and in High Latitudes. 8vo. [Montreal 1887]; Notes upon Warping of the Earth's Crust in its relation to the Origin of the Basins of the Great Lakes. 8vo. 1887. The Author. Zeiller (R.) Études des Gîtes Minéraux de la France. Bassin Houiller de Valenciennes. Description de la Flore Fossile. 2 vols. 4to. Paris 1888. Le Ministre des Travaux Publics, Paris. June 14, 1888. The Right Hon. the EARL OF ROSSE, Vice-President, in the Chair. The Right Hon. John Hay Athol Macdonald (Lord Advocate), Mr. Thomas Andrews, Mr. James Thomson Bottomley, Mr. Charles Vernon Boys, Professor Arthur Herbert Church, Professor Charles Lapworth, Professor William Ramsay, Mr. Thomas Pridgin Teale, Mr. William Topley, Professor Henry Marshall Ward, and Mr. William Henry White were admitted into the Society. The Presents received were laid on the table, and thanks ordered for them. I. "The Minimum-point of Change of Potential of a Voltaic Couple." By G. GORE, F.R.S. Received May 26, 1888. In a previous communication on "The Effect of Chlorine on the Electromotive Force of a Voltaic Couple" (Roy. Soc. Proc.,' May 3rd, 1888), I described a phenomenon which I now venture to term the "Minimum-point of Change of Potential of a Voltaic Couple." In that description a "thermo-electric pile" is mentioned as having been used for the purpose of balancing the electromotive force of the couple, whilst finding the "minimum-point of change.” As very few persons possess a thermo-electric pile suitable for the purpose, I have devised and employed the following arrangement by means of which the use of the pile may be dispensed with. Take a voltaic couple, composed of an unamalgamated strip or stout wire of zinc or magnesium (the latter is usually the best), and a small sheet of platinum, immersed in distilled water; balance its electric potential through an ordinary galvanometer by that of a precisely similar couple composed of portions of the same specimens of the same metals, immersed the same moment as the other pair in a separate quantity of the same water, and gradually add to one of the two cells sufficiently small and known quantities of an adequately weak solution of known strength in a portion of the same water, of the substance to be used, until the balance is upset, and take note of the proportions of the substance and of water then contained in that cell. It is more easy to successively dilute than to successively |