42. By what means may the air of a room be artificially heated or artificially cooled? In describing methods of artificially heating or cooling dwelling rooms, point out the objections (if any) to such methods. (60) 43. What are the various diseases which affect wheat, barley, and maize ? What are the dangers to health which may be caused by the use of such diseased grain when used as food? (60) 44. Discuss the effects of exercise in the human body upon (a) the elimination of nitrogen, (b) the elimination of carbon, (c) the skin. (60) 45. What are the reasons commonly put forward both in favour of and against the construction of "back to back "houses? State your own views on the subject, giving your reasons. (60) 46. What is the object of making the section of a sewer oviformı, and how is the hydraulic mean depth of flow determined in the case of such a sewer? (60) Honours. You are not permitted to attempt more than five questions. NOTE. No candidate will be credited with a success in this examination who has not obtained a previous success in Stage 3, or in Honours, of the same subject. Those candidates who do well in the following paper will be admitted to a practical examination held at South Kensington or some other centre. Candidates admissible to that examination will be so informed in due course. No candidate will be classed in Honours who is not successful in the practical examination. 61. Explain what is meant by (a) specific heat, and (b) latent heat of a substance. How is the specific heat of bodies determined? A piece of iron weighing 20 ozs. at a temperature of 98° C. is immersed in 60 ozs. of water at the temperature of 17° C. After the temperature had become uniform, that of the cooling water is found to be 20° C. What is the specific heat of the iron? (80) 62. If you were consulted as to the establishment of an institution for the open-air treatment of tuberculosis, what considerations, derived respectively from Geology and Meteorology, would guide you in your choice of a site? (80) 63. What are the essentials demanded of a disinfectant? Describe in detail the procedure you would recommend for the efficient disinfection of a room recently occupied by a tuberculous person. What volume of sulphur dioxide 64. An outbreak of smallpox occurs in a town of 55,000 inhabitants; 1,260 cases occur in 27 days, and of these 680 die. What is the proportion of cases and of deaths per thousand of the population for this period, and also per annum at the same rate? (80) 65. State what special dangers to health are involved in the manufacture of (a) pottery, (b) vulcanised india-rubber goods. What preventive measures should be adopted in each case? (80) 66. What are the conditions which render a house dangerous to health so as to be unfit for habitation? Describe the procedure under the Housing of the Working Classes Acts in dealing with (a) an insanitary area, (b) an insanitary dwelling. (80) PRACTICAL EXAMINATION. The time allowed for this paper is four hours. 1. Examine the sample of water marked A. (1) Qualitatively (including physical characters). (a) Hardness, total and removable, expressed as (b) Chlorine, in parts per 100,000. (c) Free Ammonia, in parts per 100,000. Nitrites are absent. Report in detail on the fitness or otherwise of the water for drinking purposes, giving your reasons. 2. Examine the sample of water marked B for Lead, and, if any is present, estimate the quantity. Give your results in grains per gallon. 3. Name and give a brief account of the appearance of, lifehistory, and the symptoms which the parasites shown under the microscopes A. and B. produce in the human being. u 56905. P SUBJECT XXVI. ELEMENTARY SCIENCE OF COMMON LIFE (CHEMISTRY). INSTRUCTIONS. Read the General Instructions on page 3. You are permitted to answer only eight questions, of which six must be taken from division A. and two from either B. or C. The time allowed for this paper is three hours. A. QUESTIONS ON SECTIONS I. TO VIII. OF THE SYLLABUS. 1. Name the standards of length, weight and volume in the metric system, and explain their relationship to one another. What is the approximate metric equivalent of an ounce, a foot and a pint? (12) 2. Explain the meaning of the term relative density. How would you determine the relative density of an egg and of brine? (10) 3. How would you show experimentally that a red-hot cinder loses heat by radiation and by convection? (10) 4. Sketch the apparatus you would use, and explain how you would show that water will boil below 100° C. when the pressure above it is lowered, and above 100° C. when the pressure is raised. (12) 5. What becomes of the oxygen when charcoal is burned in air contained in a vessel inverted in water? In what respects would the remaining gas differ from common air? (10) 6. If air be led slowly over a weighed piece of copper gauze heated in a tube, what will happen? What conclusions can be drawn from the results of the experiment? (12) 7. What change is observed in the volume of a gas when (a) the pressure, (b) the temperature, respectively, is increased? Sketch an apparatus in which the effect of change in temperature on the volume of a gas can be shown. (14) 8. The burning of sulphur in oxygen is not attended by any permanent alteration in the volume of the gas. After extinction of the sulphur flame, what experiments would you make in an attempt to account for (a) the burning of the sulphur, (b) the disappearance of part of it, (c) the failure of the remainder, if any, to burn? (12) 9. Why is part only of the air said to be active and not the whole? Supplement your explanation by an account of two experiments which justify it? (12) 10. When a vessel containing ice is brought into a warm room moisture appears on the outside. How can it be proved that this moisture is water, and that it comes from the surrounding air? How can the presence of water vapour in the air be explained? B. QUESTIONS ON SECTION IX. OF THE SYLLABUS. (12) 11. Mention six common alloys, name the metals present in each, and the chief uses to which these alloys are applied. (12) 12. Explain how common coal gas is made. What are the other chief products obtained at the same time from the coal? (14) 13. What will happen to paraffin oil and to olive oil respectively when boiled with an alkali? Name the alkali you would use in such an experiment and describe the chief products of its action. (12) 14. Describe some experiment by which you can show that different metals conduct heat more or less readily. Which is the best conductor of heat? (12) C.-QUESTIONS ON SECTION X. OF THE SYllabus. 15. How can the distillate from beer be freed from water, recognised as alcohol, and proved to contain carbon and hydrogen among its constituents? (12) 16. How would you distinguish a vegetable acid from a vegetable base? Write the names of four vegetable acids, and mention the sources from which they may be obtained. (12). 17. Describe briefly two processes by which you could obtain a specimen of stearic acid. Mention the chief uses of stearic acid. (12) 18. Cane sugar and beet sugar are popularly supposed to be different substances; how could you show that they consist essentially of the same substance in different degrees of purity? (14) All figures must be drawn on the single sheet of drawing paper supplied. The tracing paper may be detached for use in working the problems, but must be carefully re-attached. The constructions should be very accurate, and distinctly and neatly finished in pencil. The construction lines must be shown. Careless work or work done with soft or blunt pencils will receive little credit. Lines parallel or perpendicular to others may be drawn mechanically without showing any construction. Lines may be bisected by trial. In obtaining numerical answers, graphical constructions may be supplemented by arithmetic. A table of logarithms and functions of angles and useful constants (see pages 286 to 291) is supplied to each candidate. Questions marked (*) have accompanying diagrams. Stage 1. The examination in this subject lasts for four hours. You must not attempt more than eight questions in all, and of these Nos. 1, 7, and 9 must be three; that is to say, you are allowed to take not more than five questions in addition to Nos. 1, 7, and 9. 1. The component of a vector has the value x= 3 cos 35°. Determine x by constructing the angle and without using the tables. Now take cos 35° from the tables, calculate x, and find the percentage error in your first answer. (9) *2. Construct and complete the geometrical pattern shown, making the side aa of the regular hexagon 3 cm. long, and not copying the diagram. Mark the junctions of the circular arcs. (13) |