True Apparent Places of Thirty-seven of the Principal Fixed Stars for every Tenth Day of the Year. -The Upper Culmination at Greenwich. Epoch. Jan. 1 36 19.14 45 7.5 14 59.08 57 30.0 58 5.96 2 33.8 49 22.47 24 50.9 57 19.15 24 16.2 Right Asc. Dec. South. Right Asc. Dec. North. Dr. Young's Refractions, the Barometer being at 30 inches, and the internal Thermometer at 50, or the external at 47 degrees; with the Corrections for + one inch in the Barometer, and fór · one degree in the Thermometer of Fahrenheit. From page 19 of Vol. I. of Pearson's Practical Astronomy. .82 12.6 .80 12.3.79 12.1 40 5 30 11.1 .71 10.8 .69 10.6 .67 10.4 .65 10.2 .64 50 8 45 17.6 1.19 2 0 18 29 38 3.2 6 0 8 32 17.2 1.15 12 5 18 5 37 3.1 10 8 20 16.8 1.11 10 17 43 36 3.0 20 8 9 16.4 1.09 15 17 21 36 2.9 30 7 58 16.0 1.06 20 17 0 35 2.8 40 7 47 15.7 1.03 25 16 40 34 2.8 50 7 37 15.3 1.00 30 16 21 33 2.7 7 0 7 27 15.0 .98 13 35 16 2 33 2.7 40 15 43 32 2.6 45 15 25 32 2.5 50 15 8 31 2.4 2.3 40 4 35 9.2 .56 9.1 .55 04 28.1 9.00 .556 30 10 4 24.4 8.86.548 31 20 4 20.8 8.74 10 7 17 14.6 .95 30 4 17.3 8.63.533 33 - 8 8 8 8 8 8 8 8 8 8 7 8 8 5 8 7 8 8 8 8 8 5 8 8 8 7 7 8 .541 32 2 30.5 5.04 .305 2 23.2 4.79 .290 2 16.5 4.57 .276 2 10.1 4.35 .264 2 4.2 4.16 .252 1 58.8 3.97 .241 1 53.8 3.81 .230 1 49.1 3.65 .219 1 44.7 3.50 .209 1 40.5 3.36 .201 1 36.6 3.23 .193 1 33.0 3.11.186 1 29.5 2.99 .179 1 26.1 2.88 .173 1 23.0 2.78 .167 1 20.0 2.68 .161 1 17.1 2.58 .155 1 14.4 2.49 .149 1 11.8 2.40 .144 1 9.3 2.32.139 1 6.92.241.134 44 45 58.1 1.95.116 42 1 4.6 2.16.130 55 40.8 1.36.082 67 24.7 .83.050 79 11.2 56 39.3 1.31.079 68 23.5 .79.047 80 10.2 .34 1 0.3 2.02.120 57 37.8 1.26.076 69 22.4 .75.045 81 58 36.4 1.22.073 70 59 35.0 1.17 .070 71 33.6 1.12.067 72 .38 .023 .018 4.1 .14 .008 1.0 .03 0.0 .00 52 45.4 1.52.090 65 27.2 53 43.8 1.47.088 66 25.9 54 42.2 1.41.085 The correction for an increase of altitude of one inch in the barometer, or for a depression of one degree in the thermometer, is to be added to the tabular refraction; but when the barometer is lower than 30 inches, or the thermometer higher than 47 degrees, the correction becomes subtractive. When great accuracy is required, 0.003 inch should be deducted from the observed height of the barometer for each degree that the thermometer near it is above 50 degrees, and the same quantity added for an equal depression. Logarithm for converting Sidereal into Mean Solar Time +9.9988126. A second of time at the Equator contains 1521 feet. Mean Solar into Sidereal Time + 0.0011874. ANIMAL ELECTRICITY. By Professor Joseph Lovering. ON account of the close relations, not to say the actual identity, of electricity and magnetism, let no one confound the subject of Animal Electricity, as expounded in physical science, with that of Animal Magnetism. Of Animal Magnetism we know little, and have still less to say. Animal Electricity is a branch of inductive science to which large contributions have been made within the last twenty years. Our plan is to consider, first, that class of animals in which there are distinct electrical organs, and an electrical lobe in the brain to control them; secondly, that animal current which depends on the general organization, as in the frog; and thirdly, the muscular current. I. Animals with distinct Electrical Organs. This peculiarity is confined exclusively to fishes. There are five different kinds of fishes which possess the remarkable power, even in their normal state, of originating electrical currents. They are known by the names of the torpedo, or electric ray, the gymnotus, or electric eel, the Silurus electricus, Tetrodon electricus, and the Trichiurus electricus. The torpedo and gymnotus have been studied with particular attention. The Silurus electricus is described and delineated by Broussonet,* under the name of trembleur, and more recently by Rudolphi and Müller. The other two are less known. The reader who desires to pursue the study of these fishes will find valuable references in the notes to the chapter on animal electricity, in. Bird's Elements of Natural Philosophy. We shall confine our remarks to the torpedo and the gymnotus. The torpedo, a member of the ray family, inhabits the Mediterranean, the North Sea, the waters which wash the coast of France, and is occasionally found on the Atlantic coast of America, in the neighbourhood of Cape Cod and Martha's Vineyard. It is common in the markets of Rome, and is eaten by the poorer classes. The numbness or shock which this fish is capable of producing in those who touch it has been long known. Aristotle and Pliny describe it in their Natural Histories. On account of this power it is vulgarly called the trembler and the magician-fish. Before the discovery of the Leyden jar, it was supposed, to account for the benumbing power of the torpedo, that it sent forth prickly particles, or that it struck like a bent spring, or like a body in very rapid vibration. Steffano Lorenzini, who, with Redi, first studied the torpedo anatomically, published his observations on it in 1678. He says, "The chief wonder of this animal, and that which gives it its name, is the benumbing faculty which is seated in the two semicircular or falcated muscles on each side of the * Hist. de l'Acad. des Sciences, 1782. † Osservazioni intorno alle Torpedini, fatte de Steffano Lorenzini Fiorentino. Firenze, 1678. An English translation was published at London, in 1705. thorax, which consists of fibres, irregular, but as large as a goose-quill, and made up of bladders filled with a kind of water; one end of these fibres being fixed to the skin of the belly, and the other to that of the back, on which may be plainly seen the vestigia of the fibres' ends. Now, when the fish contracts those fibres, there issue out corpuscles, fitted to the pores of a man's skin, so as to enter upon immediate contact, but not otherwise, and disturb the posture of the parts, and to cause pain as when one's elbow is hit or knocked, and this comes most by the fingers' ends, because these are ends of tendons. And this pain is more or less, as the contraction of the fibres have emitted more or less." Musschenbroek, who, with Cuneus and Kleist, invented the Leyden jar in 1700, at once recognized the analogy in the shocks of this electrical vial and of one of the electrical fishes. In 1773, Walsh * published a letter addressed to Franklin, which gives an account of some experiments made on the torpedo at La Rochelle and the Isle of Ré. At this time the phenomena of friction-electricity were well known, and Walsh perceived and asserted the electrical character of the powers of the torpedo. By his experiments he discovered that the shock could be given through electrical conductors, but not through nonconductors. He proved the different electrical states of the breast and back of the fish, and showed that a connection between the upper and lower surfaces of the body is necessary in order to obtain the best shock, and that the shock, when the fish was in air, was four times as strong as when it was in water. Walsh concludes his letter in these words: -- "I rejoice in addressing these communications to you. He who predicted and showed that electricity wings the formidable bolt of the atmosphere, will hear with attention that in the deep it speeds a humbler bolt, silent and invisible. He who analyzed the electrified phial will hear with pleasure that its laws prevail in animal phials. He who by reason became an electrician will hear with reverence of an instinctive electrician, gifted in its birth with a wonderful apparatus, and with skill to use it." In the same year, John Hunter f made, at the request of Walsh, an anatomical examination of the torpedo. Hunter found that two sets of electrical organs run along the length of the body. Each set consists of plates amounting, in one case, to 1182. These organs appear to be under the control of the will. Hunter observed that the nerves connected with these organs are larger than any except those on which the important sense of seeing depends, or which are associated with great muscular action. He found that the electrical organs were not essential to any of the purposes of life except the preservation of the electrical power. In all other respects the animal thrives as well if the electrical organ is cut out. In 1775,‡ Ingenhouz published some account of the torpedoes caught by him near Leghorn, twenty miles from the shore. He gave a Leyden shock to the sailors, who at once declared its resemblance to those with which they were more * Phil. Trans., 1773. See, also, Borelli, De Motu Animalium. † Phil. Trans., 1773. Phil. Trans., 1775. |