Magnetism. 1. What do you understand by the term magnetic polarity? 2. When a magnetic needle is suspended horizontally in London, in what direction will it point? You are to show here that you understand the difference between the geographical meridian and the magnetic meridian. 3. What is the meaning of the term coercive force? You are required to illustrate its action by naming some substances which possess it in a high degree, and other substances which possess it in a low degree. 4. State all you know regarding the composition and the action of the loadstone or natural magnet. Frictional Electricity. 5. Give a clear definition of the terms electric conduction and electric induction. 6. Supposing you were required to develop induced electricity and to prove its existence, how would you do it? 7. Supposing you were required to test the quality of the electricity with which an insulator is charged, how would you do it? 8. What occurs when you whisk the resinous plate of an electrophorus with a fox's brush? The plate being excited, how will you obtain the spark of the electrophorus? 9. Describe an experiment which shall illustrate the action of the electric condenser. Voltaic Electricity. 10. Describe the simplest means known to you whereby a voltaic current can be generated. II. After the current has been generated, if asked to give some visible proof of its existence, how will you do it? 12. State what you know about the electric telegraph. 13. State what you know about the process of electro-plating. 14. Supposing you wished to intensify the electric current obtained by the simplest means employed in answer to Question 10, how would you do it? Second Stage or Advanced Examination. INSTRUCTIONS. Read the General Instructions at the head of the Elementary paper. You are only permitted to attempt eight questions. You may only select two in magnetism, three in frictional electricity, and three in voltaic electricity. The value attached to each question is the same. Magnetism. 21. If you were asked to prove that the polarity of a bar-magnet not only belongs to it as a whole, but is also resident in its smallest particles, how would you do it? 22. Describe the earth as a magnet. State what is known to you regarding its magnetic poles and equator, and how a dipping needle behaves at various points of the earth's surface. 23. Three bar-magnets, possessing strengths represented by the numbers 1, 2, 3, respectively, act in succession from the same distance on a sphere of soft iron. The attractions in the three cases are accurately measured. Write down the numbers which will express the relation they bear to each other. Give a reason for the result. 24. A bar-magnet placed at right angles to the magnetic meridian acts upon a short magnetic needle placed at a considerable distance. The axis of the magnet prolonged strikes the point of suspension of the needle. The needle is deflected, and different magnets being employed different deflections are obtained. You are required to deduce from these deflections the relative strengths of the magnets. Frictional Electricity. 25. A long brass cylinder is supported horizontally by an insulating stand. On one end of the cylinder rests a weight which can be lifted off by means of a silk thread. Over the other end is brought a glass tube which has been rubbed with silk. On lifting the weight and testing it, it is found electrified. Explain the whole process. 26. You are provided with a tumbler of good insulating glass with some paste and tin foil, and are required to form with these materials a Leyden jar. When constructed you are to charge and discharge the jar. Describe the whole process. 27. Six such jars are in your possession. You are required to arrange them so as to form a cascade battery. You are to charge and discharge the battery. How will you accomplish all this? 28. You are required to ignite guncotton by Lord Mahon's "returning stroke. How will you arrange the experiment?" 29. The knob of a Leyden jar is connected with the prime conductor of an electrical machine. The outer coating of the jar is clasped by your left hand. You are required to attract a freely-suspended lath by your right hand. How will you proceed? Voltaic Electricity, 30. To measure the strength of a voltaic current, Faraday employed a voltameter. Describe the instrument, and state the principle of its action. 31. When you employ a cell formed of zinc and platinum and dilute sulphuric acid, the current at its commencement is strong; it diminishes rapidly in strength, and finally almost ceases. What is the cause of this phenomenon? 32. When the resistance of the external circuit of a voltaic battery is vanishingly small, a single cell will produce as strong a current as a hundred cells connected together in series. Show how this follows from the law of Ohm. 33. How can the resistance of the external circuit be rendered "vanishingly small?” Show the bearing of your answer upon the "earth circuit" of the electric telegraph. 34. Describe an experimental arrangement which shall enable you to exhibit some of the principal phenomena of Faraday's induced currents. Honours Examination. INSTRUCTIONS. You are permitted to attempt all or any of the questions. 41. Describe some of the experiments which have been made to illustrate the charging and discharging of submarine cables. Describe the artificial cable constructed by Mr. Cromwell Varley, and explain its mode of action. 42. A Grove's battery is placed at your disposal; and you are required to determine practically the electro-motive force of its cells, the resistance within the cells, and the resistance of the external circuit. What instruments will you require for this purpose, and how will you apply them? 43. Describe and explain the action of Gramme's machine, and state wherein it differs from the dynamo-machine of Siemens. 44. Describe and explain, as far as you are able, the action of Holtz's machine. 45. State fully, and illustrate by a number of examples, the law of electro-chemical decomposition, established by Faraday. Show the bearing of this law upon the Atomic Theory. SUBJECT X. INORGANIC CHEMISTRY. EXAMINERS, PROFESSOR FRANKLAND, PH.D., D.C.L., F.R.S. AND PROFESSOR ROSCOE, B.A., PH.D., F.R.S. GENERAL INSTRUCTIONS. If the rules are not attended to, the paper will be cancelled. You may take the Elementary, or the Advanced, or the Honours paper, but you must confine yourself to one of them. Put the number of the question before your answer. The value attached to each question is indicated by a number placed at the end of the question. But a full and correct answer to an easy question will in all cases secure a larger number of marks than an incomplete or inexact answer to a more difficult one. Whenever possible, you are to express the reactions in equations. You are to give such numerical details as will show the mode of calculation. You are to confine your answers strictly to the questions proposed. Your name is not given to the Examiners, and you are forbidden to write to them about your answers. The examination in this subject lasts for three hours. First Stage or Elementary Examination. INSTRUCTIONS. You are permitted to attempt only eight questions. Of these, four at least must be from the first series, and if you are coming up under § XLV. of Science Directory for an extra payment for Laboratory practice, your claim will be decided from your answers to these questions. First Series. 1. Describe an experiment to illustrate the indestructibility of matter in the case of a burning candle. Give a drawing of the apparatus you would use. (9.) 2. Hydrochloric acid is stated to be composed of equal volumes of chlorine and hydrogen united without condensation. How would you prove experimentally that this is the case (a) by analysis; (b) by synthesis. (14.) 3. I add sulphuric acid to a white salt and effervescence occurs. What may this be caused by, and what tests must I apply to ascertain the nature of the gas which is evolved. (13.) 4. If I burn a piece of sulphur in a bottle filled with air, and another piece in a bottle filled with oxygen, what shall I find in each of the bottles after the combustion is finished? Give equations. (9.) 5. Describe two processes for the preparation of chlorine. Give an equation and a sketch of the apparatus in each case. (11.) 6. Into separate test glasses containing dilute hydrochloric acid I put the following substances :-Zinc, chalk, marble, common salt, charcoal, iron, and gold. Mention the chemical changes which take place and give equations. (13.) Second Series. 7. Air contains 23 per cent. of its weight of oxygen. How many grams of phosphorus are needed to burn out the whole of the oxygen in 100 grams of air when the highest oxide of phosphorus is formed. P = 31. (11.) chlorate 8. Calculate the percentage composition of potassium (chlorate of potash). (K = 39. Cl = 35'37. O = 16.) (9.) 9. How would you prove that the gas obtained by pouring sulphuric acid upon ferrous sulphide contains both sulphur and hydrogen? (13.) 10. Draw the graphic formulæ of the following compounds :-Ammonia, water, sulphuretted hydrogen. Give the active atomicity of each element in the following compounds :- CH4, SO2Ho2, PF5, Cr F6, and SO2. II. Express in words the meaning of the following equation : (13.) (8.) 12. Classify the following substances into elements and compounds :— Steam, ice, sulphur, hydroxyl, ammonia, common salt, marble, and carbonic anhydride. (12.) Second Stage or Advanced Examination. INSTRUCTIONS. Read the General Instructions at the head of the Elementary paper. You are only permitted to attempt eight questions. Of these four at least must be from the first series, and if you are coming up under § XLV. of the Science Directory for an extra payment for Laboratory practice, your claim will be decided partly from your answers to these questions. First Series. 21. Explain, both by description and by equations, the reactions which occur and the properties of the products obtained when strong sulphuric acid is heated together with (1) copper; (2) platinum; (3) fluor-spar; (4) chalk; (5) flint. (12.) 22. A powdered mineral when mixed with carbonate of soda and heated on charcoal before the blowpipe gives a bright malleable metallic bead. This when boiled with nitric acid yields a white insoluble powder. What metal do these reactions indicate, and what confirmatory tests would you use? (11.) 23. Describe verbally and by equations the changes (if any) which take place when the following elements are heated to redness in a current of air-Phosphorus, arsenic, platinum, lead, iron, and (12.) 24. Explain minutely the processes you would adopt for the detection of a cadmium compound when present in solution together with a copper salt. nickel. (15.) 25. Describe the manufacture of hydrochloric acid, give equations and sketches of the plant or apparatus employed. (15.) Second Series. 26. What means would you adopt to obtain soluble silicic acid from flint? How can the former compound be converted into insoluble silica? (12.) 27. Give the absolute, latent, and active atomicity of each element in the following compounds :-CO, PC, As,O,, HCl, SH, ON, MnCl2, and Cu2Cl2. (12.) 28. Give the formulæ, mode of preparation, properties and molecular weights of the two chlorides of mercury. (Hg = 200.) 29. Draw the graphic formulæ of the following compounds : (SO, (Na O) SO, (Na O) SS" O (Na O): (11.) meerschaum, tricalcic diphosphate, and chromic chloride. (11.) 30. Name and formulate the compound radicals which you assume to be present in the following compounds :-Sulphuric acid, ammonic chloride, nitric acid, cupric carbonate, plumbic nitrate, and microcosmic salt. (10.) |